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Thermostats

Robertshaw makes the only hi flow balanced sleeve thermostat with stress-free construction, the Power Pill®, one-piece bypass poppet, short-stroke piston and contoured strut.
  • Robertshaw 330 series hi flow balanced sleeve thermostat
    Quick shop

    Why Robertshaw? Because we make a hi flow pump and its unique three port construction or "balanced sleeve" design equalizes the system pressures above and below the thermostat’s moving valve. Therefore the thermostat is pressure balanced and will respond to system temperatures only. No other thermostat does this.

    Other Features of a Robert Shaw Thermostat:

    1) Stress-free construction. Robertshaw makes the thermostat's strut assembly from brass, not stainless steel, because brass can be bradded to the housing with heat instead of sledge hammer-like stress. This technique permits two brads per strut. Other manufacturers forcefully attach the struts to the housing with intense, metal-weakening pressure on the struts, binding each strut in only one spot.

    2) The Power Pill®. This is the heart of a Robertshaw thermostat. It detects minute changes in the temperature of the coolant, and quickly activates a precision-engineered stem or piston to open and close the thermostat valve.

    3) One-piece bypass poppet. With other thermostats, the bypass valve stem is welded on. The weld tends to fail under stress. To eliminate this problem, Robertshaw manufactures the entire copper cup and bypass stem from a single piece of metal.

    4) Short-stroke piston. In conventional thermostats, the piston must make a large stroke to open the thermostat far enough for adequate coolant flow. But the long stroke compromises durability. Robertshaw engineers achieved a shorter stroke with a uniquely-designed flange and poppet. This design increases the longevity of the thermostat, yet still allows adequate coolant circulation.

    5) Contoured strut. Making the strut assembly from brass instead of steel provides another benefit: brass, being more malleable than steel, can be precisely formed to maximize coolant flow.

    6) Uniform quality. Robertshaw builds all thermostats to OEM standards -- so your replacement thermostat is identical to those used in new Fords, Chryslers, and other cars.

    The Power Pill

    At the heart of a Robertshaw thermostat is the power pill. Its job: to detect minute changes in the temperature of the coolant, and to quickly activate a precision-engineered piston that opens and closes the thermostat valve. Compared to the thermal elements in some thermostats, Robertshaw's Power Pill® has major advantages:

    1) Rapid response. The Power Pill's piston is activated by a temperature-sensitive mixture of metallic powder and wax. Some thermostats use an all-wax charge, which responds slowly to temperature changes. Other brands mix copper powder with the wax for faster response, but the copper quickly separates from the wax. Robertshaw developed a process to maintain suspension of the copper powder in the wax, so the fast response doesn't deteriorate and the thermostat will not "stick-open" to cause the engine to run cool.

    2) Reliable performance. Most manufacturers use a one-piece rubber diaphragm to seal the charge and drive the piston. If the rubber part ruptures, the thermostat fails. Robertshaw uses two separate parts: a diaphragm to seal the wax, and a stem seat or plug that drives the piston. Rubber material for each part is formulated especially to meet each part's unique requirements. Wear or damage to the stem seat still allows the thermostat to operate satisfactorily.

    3) Precise performance. Every Robertshaw Power Pill is calibrated to bring the thermostat's start-to-open temperature within strict tolerances.

    Make CID Ltr Year
    AM GENERAL 395 6.5 1996-2000
    AMERICAN MOTORS 196 3.2 1961-1970
    AMERICAN MOTORS 232 3.8 1965-1979
    AMERICAN MOTORS 258 4.2 1976-1988
    AMERICAN MOTORS 304 5.0 1970-1979
    AMERICAN MOTORS 343 5.6 1967-1969
    AMERICAN MOTORS 360 5.9 1970-1978
    AMERICAN MOTORS 390 6.4 1969-1970
    AMERICAN MOTORS 401 6.6 1971-1974
    BUICK 173 2.8 1980-1986
    BUICK 181 3.0 1982-1985
    BUICK 196 3.2 1978-1979
    BUICK 231 3.8 1978-1985
    BUICK 250 4.1 1968-1975
    BUICK 252 4.1 1980-1984
    BUICK 260 4.3 1975-1984
    BUICK 265 4.3 1980-1981
    BUICK 267 4.4 1981-1982
    BUICK 300 4.9 1964-1967
    BUICK 301 4.9 1977-1980
    BUICK 305 5.0 1977-1991
    BUICK 307 5.0 1980-1990
    BUICK 340 5.6 1966-1967
    BUICK 350 5.7 1968-1995
    BUICK 400 6.6 1967-1969
    BUICK 403 6.6 1975-1979
    BUICK 430 7.1 1967-1969
    BUICK 455 7.5 1969-1976
    CADILLAC 250 4.1 1987-1988
    CADILLAC 252 4.1 1980-1982
    CADILLAC 260 4.3 1985
    CADILLAC 273 4.5 1988-1992
    CADILLAC 300 4.9 1991-1994
    CADILLAC 305 5.0 1991-1992
    CADILLAC 307 5.0 1986-1990
    CADILLAC 350 5.7 1978-1995
    CADILLAC 390 6.4 1963
    CADILLAC 429 7.0 1964-1967
    CHECKER 229 3.8 1980-1982
    CHECKER 230 3.8 1968
    CHECKER 250 4.1 1969-1979
    CHECKER 267 4.4 1980-1982
    CHECKER 305 5.0 1978-1982
    CHECKER 307 5.0 1968
    CHECKER 327 5.4 1968-1969
    CHECKER 350 5.7 1969-1982
    CHEVROLET 173 2.8 1980-1986
    CHEVROLET 194 3.2 1962-1966
    CHEVROLET 196 3.2 1978-1979
    CHEVROLET 200 3.3 1978-1979
    CHEVROLET 229 3.8 1980-1984
    CHEVROLET 230 3.8 1963-1970
    CHEVROLET 231 3.8 1978-1987
    CHEVROLET 235 3.9 1955-1962
    CHEVROLET 250 4.1 1972-1984
    CHEVROLET 260 4.3 1982-1985
    CHEVROLET 262 4.3 1975-1994
    CHEVROLET 265 4.3 1955-1957
    CHEVROLET 267 4.4 1979-1982
    CHEVROLET 283 4.6 1957-1967
    CHEVROLET 292 4.8 1973-1989
    CHEVROLET 305 5.0 1976-1995
    CHEVROLET 307 5.0 1968-1990
    CHEVROLET 327 5.4 1962-1969
    CHEVROLET 348 5.7 1958-1961
    CHEVROLET 350 5.7 1969-1995
    CHEVROLET 395 6.5 1996-2000
    CHEVROLET 396 6.5 1968-1970
    CHEVROLET 400 6.6 1971-1980
    CHEVROLET 402 6.6 1971-1972
    CHEVROLET 409 6.7 1961-1965
    CHEVROLET 427 7.0 1966-1969
    CHEVROLET 454 7.4 1973-1990
    DODGE 170 2.8 1961-1968
    DODGE 225 3.7 1961-1968
    DODGE 318 5.2 1979-1980
    DODGE 360 5.9 1979-1980
    DODGE 440 7.2 1979
    EAGLE 150 2.5 1989
    FORD 144 2.4 1960-1964
    FORD 170 2.8 1960-1972
    FORD 200 3.3 1963-1983
    FORD 221 3.6 1963-1984
    FORD 232 3.8 1982-194-1984
    FORD 240 3.9 1965-1974
    FORD 242 4.0 1968-1969
    FORD 250 4.1 1969-1980
    FORD 255 4.2 1980-1982
    FORD 260 4.3 1963-1964
    FORD 289 4.7 1963-1968
    FORD 300 4.9 1968-1994
    FORD 302 5.0 1968-1989
    FORD 351 5.8 1975-1989
    FORD 360 5.9 1968-1976
    FORD 390 6.4 1967-1971
    FORD 420 6.9 1983-1987
    FORD 427 7.0 1967-1969
    FORD 428 7.0 1967-1970
    FORD 429 7.0 1968-1973
    FORD 445 7.3 1988-1994
    FORD 460 7.5 1972-1994
    GMC 200 3.3 1978-1979
    GMC 229 3.8 1980-1984
    GMC 231 3.8 1978-1984
    GMC 250 4.1 1973-1984
    GMC 262 4.3 1985-1994
    GMC 267 4.4 1980-1982
    GMC 292 4.8 1973-1989
    GMC 305 5.0 1976-1994
    GMC 350 5.7 1969-1994
    GMC 395 6.5 1996-2000
    GMC 400 6.6 1975-1980
    GMC 454 7.4 1973-1990
    JEEP 126 2.1 1986
    JEEP 134 2.1 1946, 1961-1983
    JEEP 150 2.5 1984-2002
    JEEP 225 3.7 1968-1974
    JEEP 226 3.7 1962-1963
    JEEP 230 3.8 1962-1990
    JEEP 232 3.8 1976-1986
    JEEP 242 4.0 1989-2006
    JEEP 258 4.2 1972-2006
    JEEP 304 5.0 1972-1981
    JEEP 350 5.7 1969-1973
    JEEP (but not grand cherokee) 360 5.9 1972-1991
    JEEP 401 6.6 1974-1978
    LINCOLN 232 3.8 1982
    LINCOLN 302 5.0 1977-1982
    LINCOLN 351 5.8 1980
    LINCOLN 460 7.5 1969-1978
    MERCEDES-BENZ 116 1.9 1960-1963
    MERCURY 144 2.4 1962-1963
    MERCURY 170 2.8 1962-1972
    MERCURY 200 3.3 1968-1983
    MERCURY 221 3.6 1962-1963
    MERCURY 232 3.8 1982-1983
    MERCURY 250 4.1 1969-1980
    MERCURY 255 4.2 1980-1982
    MERCURY 260 4.3 1963-1964
    MERCURY 289 4.7 1964-1968
    MERCURY 302 5.0 1969-1986
    MERCURY 351 5.8 1970-1986
    MERCURY 390 6.4 1967-1970
    MERCURY 410 6.7 1967
    MERCURY 427 7.0 1967-1968
    MERCURY 428 7.0 1967-1970
    MERCURY 429 7.0 1969-1973
    MERCURY 460 7.5 1972-1978
    OLDSMOBILE 151 2.5 1982-1992
    OLDSMOBILE 173 2.8 1980-1986
    OLDSMOBILE 181 3.0 1982-1985
    OLDSMOBILE 215 3.5 1961-1963
    OLDSMOBILE 225 3.7 1964-1965
    OLDSMOBILE 231 3.8 1975-1987
    OLDSMOBILE 250 4.1 1973-1976
    OLDSMOBILE 252 4.1 1981-1984
    OLDSMOBILE 260 4.3 1975-1985
    OLDSMOBILE 262 4.3 1991-1992
    OLDSMOBILE 267 4.4 1981-1982
    OLDSMOBILE 305 5.0 1977-1992
    OLDSMOBILE 307 5.0 1980-1990
    OLDSMOBILE 330 5.4 1964-1967
    OLDSMOBILE 350 5.7 1975-1992
    OLDSMOBILE 371 6.1 1957-1959
    OLDSMOBILE 394 6.5 1961-1964
    OLDSMOBILE 400 6.6 1965-1975
    OLDSMOBILE 403 6.6 1977-1979
    OLDSMOBILE 425 7.0 1965-1967
    OLDSMOBILE 455 7.5 1972-1976
    PLYMOUTH 318 5.2 1979-1980
    PLYMOUTH 360 5.9 1979
    PONTIAC 140 2.3 1975-1976
    PONTIAC 173 2.8 1980-1986
    PONTIAC 215 3.5 1964-1965
    PONTIAC 229 3.8 1980-1983
    PONTIAC 230 3.8 1966-1967
    PONTIAC 231 3.8 1976-1987
    PONTIAC 239 3.9 1946-1954
    PONTIAC 249 4.1 1946-1949
    PONTIAC 250 4.1 1972-1976
    PONTIAC 252 4.1 1982
    PONTIAC 260 4.3 1975-1985
    PONTIAC 262 4.3 1985-1987
    PONTIAC 265 4.3 1980-1981
    PONTIAC 267 4.4 1981-1982
    PONTIAC 268 4.4 1950-1954
    PONTIAC 287 4.7 1955
    PONTIAC 301 4.9 1977-1981
    PONTIAC 305 5.0 1977-1992
    PONTIAC 307 5.0 1981-1989
    PONTIAC 316 5.2 1956
    PONTIAC 326 5.3 1963-1967
    PONTIAC 347 5.7 1957
    PONTIAC 350 5.7 1972-1992
    PONTIAC 370 6.1 1958
    PONTIAC 389 6.4 1965-1966
    PONTIAC 400 6.6 1972-1979
    PONTIAC 403 6.6 1977-1979
    PONTIAC 421 6.9 1963-1966
    PONTIAC 428 7.0 1967-1969
    PONTIAC 455 7.5 1972-1976

    The model list of applications for this thermostat series is so extensive it cannot be part of the search functionality. It is included here for the secondary site search feature.

    190sl, 442, 6000, 88, a100, allante, ambassador, amx, apollo, astre, astro, b100 van, b200 van, b300 van, bel air, belvedere, biscayne, blazer, bonneville, bravada, bronco, brookwood, brougham, c10 pickup, c10 suburban, c15/c1500 pickup, c15/c1500 suburban, c1500 pickup, c1500 suburban, c20 pickup, c20 suburban, c25/c2500 pickup, c25/c2500 suburban, c2500 pickup, c2500 suburban, c30 pickup, c35/c3500 pickup, c3500 pickup, caballero, calais, caliente, camaro, capri, caprice, caravelle, catalina, cb300, celebrity, centurion, century, charger, cherokee, chevelle, chevy ii, chieftain, citation, cj7, classic, club, club wagon, cobra, colony park, comanche, comet, commuter, concord, continental, coronet, corvette, cougar, country cruiser, country sedan, country squire, custom, custom 500, custom cruiser, cutlass, cutlass calais, cutlass ciera, cutlass cruiser, cutlass supreme, cyclone, d100 pickup, d100 series, d150 pickup, d200 pickup, d200 series, d300 pickup, d300 series, d350 pickup, d400 pickup, d450 pickup, dart, del ray, delmont 88, delta 88, deluxe, deville, diplomat, dj5, dj6, duster, dynamic, e-100 econoline, e-150 econoline, e-200 econoline, e-250 econoline, e-300 econoline, e-350 econoline, eagle, econoline, el camino, eldorado, electra, estate wagon, executive, express 2500, f-100 pickup, f-150 pickup, f-250 pickup, f-350 pickup, f-450 super duty pickup, f53 stripped chassis, f59 stripped chassis, f85, fairlane, fairmont, falcon, falcon sedan delivery, fc170, fiesta, firebird, fleetwood, ford 300, fury, fury i, fury ii, fury iii, g10 van, g15/g1500 van, g20 van, g25/g2500 van, g2500 van, g30 van, g35/g3500 van, g3500 van, galaxie, galaxie 500, gladiator, gran fury, gran sport, gran torino, granada, grand am, grand cherokee, grand lemans, grand marquis, grand prix, grand safari, grand wagoneer, grandville, gremlin, gs, gs 400, gs 455, gto, hornet, hummer, impala, j10, j-100, j20, j-2500, j-2600, j-2700, j-3500, j-3600, j-3700, j-3800, javelin, jeep, jeepster, jetfire, jetstar 88, jimmy, k10 pickup, k10 suburban, k15/k1500 pickup, k15/k1500 suburban, k1500 pickup, k1500 suburban, k20 pickup, k20 suburban, k25/k2500 pickup, k25/k2500 suburban, k2500 pickup, k2500 suburban, k30 pickup, k35/k3500 pickup, k3500 pickup, kingswood, laguna, lancer, laurentian, lemans, lesabre, ltd, ltd ii, m-400, m-450, magnum, malibu, marathon, marauder, mark iii, mark iv, mark v, mark vi, marlin, marquis, matador, maverick, meteor, monarch, montclair, monte carlo, montego, monterey, monza, mustang, mustang ii, nova, omega, one-fifty series, p10 series, p10 van, p100, p-100, p15/p1500 van, p20 series, p20 van, p200, p25/p2500 van, p30 series, p30 van, p300, p35/p3500 van, p-350, pacer, parisienne, park lane, pb100 van, pb150 van, pb200 van, pb250 van, pb300 van, pb350 van, phoenix, polara, premier, r10 pickup, r10 suburban, r1500 pickup, r1500 suburban, r20 pickup, r20 suburban, r2500 pickup, r2500 suburban, r30 pickup, r3500 pickup, rambler, ramcharger, ranch wagon, ranchero, regal, riviera, roadmaster, rogue, s10 blazer, s10 pickup, s15 jimmy, s15 pickup, s15 sonoma, s15 syclone, s15 typhoon, safari, savana 2500, savana 3500, scrambler, series 62, series 75 fleetwood, seville, skyhawk, skylark, special, spirit, sportwagon, sprint, st. regis, star chief, starfire, streamliner, suburban, sunbird, sunliner, super 88, super chief, super six, tahoe, tempest, thunderbird, torino, tornado, toronado, torpedo, town car, townsman, trailduster, truck, two-ten series, universal, v10 suburban, v1500 pickup, v1500 suburban, v20 pickup, v20 suburban, v2500 pickup, v2500 suburban, v30 pickup, v3500 pickup, ventura, versailles, victoria, villager, vista cruiser, volare, voyager, w100 pickup, w100 series, w150 pickup, w200 pickup, w200 series, w300 pickup, w300 series, wagoneer, wildcat, wrangler, yukon, zephyr

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  • Robertshaw 333 Series hi flow balanced sleeve thermostat
    Quick shop

    The Robertshaw 333 series thermostat has the distinction of being the only available thermostat that would accommodate the 351 Cleveland Controlled bypass system*.  A 351C provided greater water flow in the engine for a faster, more even warm-up without creating hot spots (particularly in the valve area). The bypass design controlled the water flow and temperature with less cycling and increased the flow to the radiator for improved cooling performance.   It was an ideal solution for overheating 351C found in mustangs and hot Panteras. 

    The OE Robertshaw thermostats for the OE bypass is available again.  Its made in the USA.  Yes this is a real Robertshaw 333 series.  If you want 160 degree alternative, consider the 333-substitute

    The substitute performs the same preheat function but we resized the bypass hole for more temperature options.  

    *The 400 and 351M had this feature cast into the block and did not utilize this brass bypass insert.  The cast bypass hole requires the 333 series.

    Year Make Model Eng CID VIN
    1978-1979 FORD BRONCO V8 351 H
    1984 FORD BRONCO V8 351 H
    1970-1971 FORD COBRA V8 351 M
    1971 FORD COBRA V8 351 H
    1970-1974 FORD COUNTRY SEDAN V8 351 H
    1972-1974 FORD COUNTRY SEDAN V8 400 S
    1970-1974 FORD COUNTRY SQUIRE V8 351 H
    1979 FORD COUNTRY SQUIRE V8 351 H
    1972-1974 FORD COUNTRY SQUIRE V8 400 S
    1975-1976 FORD COUNTRY SQUIRE V8 400 S
    1970-1972 FORD CUSTOM V8 351 H
    1972 FORD CUSTOM V8 400 S
    1970-1974 FORD CUSTOM 500 V8 351 H
    1976-1977 FORD CUSTOM 500 V8 351 H
    1972-1974 FORD CUSTOM 500 V8 400 S
    1975-1977 FORD CUSTOM 500 V8 400 S
    1976-1979 FORD E-100 ECONOLINE V8 351 H
    1976-1979 FORD E-150 ECONOLINE V8 351 H
    1980-1984 FORD E-150 ECONOLINE V8 351 G
    1976-1979 FORD E-250 ECONOLINE V8 351 H
    1980-1984 FORD E-250 ECONOLINE V8 351 G
    1984 FORD E-250 ECONOLINE V8 351 H
    1981 FORD E-250 ECONOLINE V8 400 Z
    1976-1979 FORD E-350 ECONOLINE V8 351 H
    1980-1984 FORD E-350 ECONOLINE V8 351 G
    1981-1982 FORD E-350 ECONOLINE V8 400 Z
    1977-1979 FORD F-100 PICKUP V8 351 H
    1981 FORD F-100 PICKUP V8 351 G
    1978-1979 FORD F-100 PICKUP V8 400 S
    1977-1978 FORD F-150 PICKUP V8 351 H
    1978-1979 FORD F-150 PICKUP V8 400 S
    1979 FORD F-150 PICKUP V8 351 H
    1981-1984 FORD F-150 PICKUP V8 351 G
    1984 FORD F-150 PICKUP V8 351 H
    1977-1979 FORD F-250 PICKUP V8 351 H
    1980-1984 FORD F-250 PICKUP V8 351 G
    1984 FORD F-250 PICKUP V8 351 H
    1978-1979 FORD F-250 PICKUP V8 400 S
    1981-1982 FORD F-250 PICKUP V8 400 Z
    1978-1979 FORD F-350 PICKUP V8 351 H
    1980-1984 FORD F-350 PICKUP V8 351 G
    1978-1979 FORD F-350 PICKUP V8 400 S
    1980-1982 FORD F-350 PICKUP V8 400 Z
    1970 FORD FAIRLANE V8 351 H
    1970 FORD FAIRLANE V8 351 M
    1970 FORD FALCON V8 351 M
    1971-1974 FORD GALAXIE 500 V8 351 H
    1972-1974 FORD GALAXIE 500 V8 400 S
    1972-1974 FORD GRAN TORINO V8 351 H
    1976 FORD GRAN TORINO V8 351 H
    1972-1974 FORD GRAN TORINO V8 351 Q
    1972-1974 FORD GRAN TORINO V8 400 S
    1975-1976 FORD GRAN TORINO V8 400 S
    1976-1977 FORD GRANADA V8 351 H
    1970-1974 FORD LTD V8 351 H
    1976-1979 FORD LTD V8 351 H
    1972-1974 FORD LTD V8 400 S
    1975-1978 FORD LTD V8 400 S
    1978-1979 FORD LTD II V8 351 H
    1977-1978 FORD LTD II V8 400 S
    1971-1973 FORD MUSTANG V8 351 H
    1970-1971 FORD MUSTANG V8 351 M
    1972-1973 FORD MUSTANG V8 351 Q
    1970-1974 FORD RANCH WAGON V8 351 H
    1972-1974 FORD RANCH WAGON V8 400 S
    1975-1976 FORD RANCH WAGON V8 400 S
    1970-1974 FORD RANCHERO V8 351 H
    1976-1979 FORD RANCHERO V8 351 H
    1970-1971 FORD RANCHERO V8 351 M
    1972-1974 FORD RANCHERO V8 351 Q
    1973-1974 FORD RANCHERO V8 400 S
    1975-1978 FORD RANCHERO V8 400 S
    1978-1979 FORD THUNDERBIRD V8 351 H
    1977-1978 FORD THUNDERBIRD V8 400 S
    1970-1974 FORD TORINO V8 351 H
    1976 FORD TORINO V8 351 H
    1970-1971 FORD TORINO V8 351 M
    1972-1974 FORD TORINO V8 351 Q
    1973-1974 FORD TORINO V8 400 S
    1975-1976 FORD TORINO V8 400 S
    1978-1979 LINCOLN CONTINENTAL V8 400 S
    1978-1979 LINCOLN MARK V V8 400 S
    1971-1973 MERCURY COLONY PARK V8 351 H
    1979 MERCURY COLONY PARK V8 351 H
    1972-1976 MERCURY COLONY PARK V8 400 S
    1971-1974 MERCURY COUGAR V8 351 H
    1975-1979 MERCURY COUGAR V8 351 H
    1970-1971 MERCURY COUGAR V8 351 M
    1972-1974 MERCURY COUGAR V8 351 Q
    1974-1978 MERCURY COUGAR V8 400 S
    1971 MERCURY CYCLONE V8 351 H
    1970-1971 MERCURY CYCLONE V8 351 M
    1979 MERCURY GRAND MARQUIS V8 351 H
    1976-1978 MERCURY GRAND MARQUIS V8 400 S
    1972-1973 MERCURY MARQUIS V8 351 H
    1978-1979 MERCURY MARQUIS V8 351 H
    1972-1978 MERCURY MARQUIS V8 400 S
    1976-1977 MERCURY MONARCH V8 351 H
    1971-1974 MERCURY MONTEGO V8 351 H
    1975-1976 MERCURY MONTEGO V8 351 H
    1970-1971 MERCURY MONTEGO V8 351 M
    1972-1974 MERCURY MONTEGO V8 351 Q
    1973-1976 MERCURY MONTEGO V8 400 S
    1971-1973 MERCURY MONTEREY V8 351 H
    1972-1974 MERCURY MONTEREY V8 400 S
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  • Robertshaw 333 Series hi flow balanced sleeve thermostat substitute & brass bypass
    Quick shop
    On sale

    The Robertshaw 333 series thermostat has the distinction of being the only available thermostat that would accommodate the 351 Cleveland controlled bypass system*.  A 351C provided greater water flow in the engine for a faster, more even warm-up without creating hot spots (particularly in the valve area). The bypass design controlled the water flow and temperature with less cycling and increased the flow to the radiator for improved cooling performance.   It was an ideal solution for overheating mustangs and hot Panteras.  For a time, due to slowing sales, Robertshaw ended production of the 333 product.

    When we discovered a hat modification and plate was sold for $125.65 without the thermostat we thought there has to be a more economical way.  We designed an alternative sized bypass that will utilize the Robertshaw 330 series hi flow thermostat in the existing 351C controlled bypass system. Simply remove your bypass and tap the new bypass into the counter-bore until it seats and install the 330 series.  That’s all there is to it. 

    Most ran these engines with a 192 degree t-stat but the 330 is series available in 160, 180 and 195.

    Insert and the Robertshaw thermostats are both Made in the USA.

    *The 400 and 351M had this feature cast into the block and did not utilize this brass bypass.  If you have the 400 or the 351M you can purchase the 330 series.  The cast bypass will be partially sealed off.

     

    Year Make Model Eng CID VIN
    1978-1979 FORD BRONCO V8 351 H
    1984 FORD BRONCO V8 351 H
    1970-1971 FORD COBRA V8 351 M
    1971 FORD COBRA V8 351 H
    1970-1974 FORD COUNTRY SEDAN V8 351 H
    1972-1974 FORD COUNTRY SEDAN V8 400 S
    1970-1974 FORD COUNTRY SQUIRE V8 351 H
    1979 FORD COUNTRY SQUIRE V8 351 H
    1972-1974 FORD COUNTRY SQUIRE V8 400 S
    1975-1976 FORD COUNTRY SQUIRE V8 400 S
    1970-1972 FORD CUSTOM V8 351 H
    1972 FORD CUSTOM V8 400 S
    1970-1974 FORD CUSTOM 500 V8 351 H
    1976-1977 FORD CUSTOM 500 V8 351 H
    1972-1974 FORD CUSTOM 500 V8 400 S
    1975-1977 FORD CUSTOM 500 V8 400 S
    1976-1979 FORD E-100 ECONOLINE V8 351 H
    1976-1979 FORD E-150 ECONOLINE V8 351 H
    1980-1984 FORD E-150 ECONOLINE V8 351 G
    1976-1979 FORD E-250 ECONOLINE V8 351 H
    1980-1984 FORD E-250 ECONOLINE V8 351 G
    1984 FORD E-250 ECONOLINE V8 351 H
    1981 FORD E-250 ECONOLINE V8 400 Z
    1976-1979 FORD E-350 ECONOLINE V8 351 H
    1980-1984 FORD E-350 ECONOLINE V8 351 G
    1981-1982 FORD E-350 ECONOLINE V8 400 Z
    1977-1979 FORD F-100 PICKUP V8 351 H
    1981 FORD F-100 PICKUP V8 351 G
    1978-1979 FORD F-100 PICKUP V8 400 S
    1977-1978 FORD F-150 PICKUP V8 351 H
    1978-1979 FORD F-150 PICKUP V8 400 S
    1979 FORD F-150 PICKUP V8 351 H
    1981-1984 FORD F-150 PICKUP V8 351 G
    1984 FORD F-150 PICKUP V8 351 H
    1977-1979 FORD F-250 PICKUP V8 351 H
    1980-1984 FORD F-250 PICKUP V8 351 G
    1984 FORD F-250 PICKUP V8 351 H
    1978-1979 FORD F-250 PICKUP V8 400 S
    1981-1982 FORD F-250 PICKUP V8 400 Z
    1978-1979 FORD F-350 PICKUP V8 351 H
    1980-1984 FORD F-350 PICKUP V8 351 G
    1978-1979 FORD F-350 PICKUP V8 400 S
    1980-1982 FORD F-350 PICKUP V8 400 Z
    1970 FORD FAIRLANE V8 351 H
    1970 FORD FAIRLANE V8 351 M
    1970 FORD FALCON V8 351 M
    1971-1974 FORD GALAXIE 500 V8 351 H
    1972-1974 FORD GALAXIE 500 V8 400 S
    1972-1974 FORD GRAN TORINO V8 351 H
    1976 FORD GRAN TORINO V8 351 H
    1972-1974 FORD GRAN TORINO V8 351 Q
    1972-1974 FORD GRAN TORINO V8 400 S
    1975-1976 FORD GRAN TORINO V8 400 S
    1976-1977 FORD GRANADA V8 351 H
    1970-1974 FORD LTD V8 351 H
    1976-1979 FORD LTD V8 351 H
    1972-1974 FORD LTD V8 400 S
    1975-1978 FORD LTD V8 400 S
    1978-1979 FORD LTD II V8 351 H
    1977-1978 FORD LTD II V8 400 S
    1971-1973 FORD MUSTANG V8 351 H
    1970-1971 FORD MUSTANG V8 351 M
    1972-1973 FORD MUSTANG V8 351 Q
    1970-1974 FORD RANCH WAGON V8 351 H
    1972-1974 FORD RANCH WAGON V8 400 S
    1975-1976 FORD RANCH WAGON V8 400 S
    1970-1974 FORD RANCHERO V8 351 H
    1976-1979 FORD RANCHERO V8 351 H
    1970-1971 FORD RANCHERO V8 351 M
    1972-1974 FORD RANCHERO V8 351 Q
    1973-1974 FORD RANCHERO V8 400 S
    1975-1978 FORD RANCHERO V8 400 S
    1978-1979 FORD THUNDERBIRD V8 351 H
    1977-1978 FORD THUNDERBIRD V8 400 S
    1970-1974 FORD TORINO V8 351 H
    1976 FORD TORINO V8 351 H
    1970-1971 FORD TORINO V8 351 M
    1972-1974 FORD TORINO V8 351 Q
    1973-1974 FORD TORINO V8 400 S
    1975-1976 FORD TORINO V8 400 S
    1978-1979 LINCOLN CONTINENTAL V8 400 S
    1978-1979 LINCOLN MARK V V8 400 S
    1971-1973 MERCURY COLONY PARK V8 351 H
    1979 MERCURY COLONY PARK V8 351 H
    1972-1976 MERCURY COLONY PARK V8 400 S
    1971-1974 MERCURY COUGAR V8 351 H
    1975-1979 MERCURY COUGAR V8 351 H
    1970-1971 MERCURY COUGAR V8 351 M
    1972-1974 MERCURY COUGAR V8 351 Q
    1974-1978 MERCURY COUGAR V8 400 S
    1971 MERCURY CYCLONE V8 351 H
    1970-1971 MERCURY CYCLONE V8 351 M
    1979 MERCURY GRAND MARQUIS V8 351 H
    1976-1978 MERCURY GRAND MARQUIS V8 400 S
    1972-1973 MERCURY MARQUIS V8 351 H
    1978-1979 MERCURY MARQUIS V8 351 H
    1972-1978 MERCURY MARQUIS V8 400 S
    1976-1977 MERCURY MONARCH V8 351 H
    1971-1974 MERCURY MONTEGO V8 351 H
    1975-1976 MERCURY MONTEGO V8 351 H
    1970-1971 MERCURY MONTEGO V8 351 M
    1972-1974 MERCURY MONTEGO V8 351 Q
    1973-1976 MERCURY MONTEGO V8 400 S
    1971-1973 MERCURY MONTEREY V8 351 H
    1972-1974 MERCURY MONTEREY V8 400 S
    Visit product page
  • Robertshaw 370 series substitute hi flow balanced sleeve thermostat
    Quick shop

    Sadly Robertshaw no longer manufactures the 370 series in all temperatures.  The difference between the 370 Series and the 330 Series was the flange diameter.  Necessity is the mother of invention so we designed an interface ring that allows you to size up your 330 and get the benefit of high flow.

    Fits Mopar, Some Ford, Lincoln, Mercury, AMC L6 Buick Nailhead

    Why Robertshaw? Because we make a hi flow pump and its unique three port construction or "balanced sleeve" design equalizes the system pressures above and below the thermostat’s moving valve. Therefore the thermostat is pressure balanced and will respond to system temperatures only. No other thermostat does this.

    Other Features of a Robert Shaw Thermostat:

    1) Stress-free construction. Robertshaw makes the thermostat's strut assembly from brass, not stainless steel, because brass can be bradded to the housing with heat instead of sledge hammer-like stress. This technique permits two brads per strut. Other manufacturers forcefully attach the struts to the housing with intense, metal-weakening pressure on the struts, binding each strut in only one spot.

    2) The Power Pill®. This is the heart of a Robertshaw thermostat. It detects minute changes in the temperature of the coolant, and quickly activates a precision-engineered stem or piston to open and close the thermostat valve.

    3) One-piece bypass poppet. With other thermostats, the bypass valve stem is welded on. The weld tends to fail under stress. To eliminate this problem, Robertshaw manufactures the entire copper cup and bypass stem from a single piece of metal.

    4) Short-stroke piston. In conventional thermostats, the piston must make a large stroke to open the thermostat far enough for adequate coolant flow. But the long stroke compromises durability. Robertshaw engineers achieved a shorter stroke with a uniquely-designed flange and poppet. This design increases the longevity of the thermostat, yet still allows adequate coolant circulation.

    5) Contoured strut. Making the strut assembly from brass instead of steel provides another benefit: brass, being more malleable than steel, can be precisely formed to maximize coolant flow.

    6) Uniform quality. Robertshaw builds all thermostats to OEM standards -- so your replacement thermostat is identical to those used in new Fords, Chryslers, and other cars. The Power Pill At the heart of a Robertshaw thermostat is the power pill. Its job: to detect minute changes in the temperature of the coolant, and to quickly activate a precision-engineered piston that opens and closes the thermostat valve. Compared to the thermal elements in some thermostats, Robertshaw's Power Pill® has major advantages:

    1) Rapid response. The Power Pill's piston is activated by a temperature-sensitive mixture of metallic powder and wax. Some thermostats use an all-wax charge, which responds slowly to temperature changes. Other brands mix copper powder with the wax for faster response, but the copper quickly separates from the wax. Robertshaw developed a process to maintain suspension of the copper powder in the wax, so the fast response doesn't deteriorate and the thermostat will not "stick-open" to cause the engine to run cool.

    2) Reliable performance. Most manufacturers use a one-piece rubber diaphragm to seal the charge and drive the piston. If the rubber part ruptures, the thermostat fails. Robertshaw uses two separate parts: a diaphragm to seal the wax, and a stem seat or plug that drives the piston. Rubber material for each part is formulated especially to meet each part's unique requirements. Wear or damage to the stem seat still allows the thermostat to operate satisfactorily.

    3) Precise performance. Every Robertshaw Power Pill is calibrated to bring the thermostat's start-to-open temperature within strict tolerances.

    Thermostat Applications
    Make Model Year CID Liters
    american motors super six, rambler, american,   1961-1962 196 3.2
    american motors rambler 1959-1960 196 3.2
    american motors american 1959-1968 196 3.2
    american motors rebel 1959-1970 250 4.1
    buick various 1954-1956 264 4.3
    buick special 1957-1961 364
    5.9
    buick electra gran sport , invicta, lesabre, riviera, skylark wiildcat 1959-1966 401 6.6
    buick electra gran sport , invicta, lesabre, riviera, wiildcat 1963-1966 425 7.0
    buick century roadmaster, skylark, super 1953-1956 322 5.3
    cadillac deville. eldorado  1953-1962 331 5.4

    cadillac series 60 fleetwood 1950-1964 331 5.4
    cadillac series 61 1950-1951 331 5.4
    cadillac series 62 1952-1962 331 5.4
    cadillac series 70 fleetwood eldorado 1958-1962 365 6.0
    chevrolet g20 van 1983-1993 379 6.2
    chevrolet g30 van 1983-1993 379 6.2
    chevrolet k10 pickup 1982-1986 379 6.2
    chevrolet k10 suburban 1982-1986 379 6.2
    chevrolet p20 van 1982-1989 379 6.2
    chevrolet p30 van 1982-1993 379 6.2
    chevrolet r10 pickup 1987 379 6.2
    chevrolet r10 suburban 1987-1988 379 6.2
    chevrolet r20 pickup 1987-1988 379 6.2
    chevrolet r20 suburban 1987-1988 379 6.2
    chevrolet r30 pickup 1987-1988 379 6.2
    chevrolet v10 pickup 1987    
    chevrolet v10 suburban 1987-1988 379 6.2
    chevrolet v20 pickup 1987 379 6.2
    chevrolet v20 suburban 1987-1988 379 6.2
    chevrolet v30 pickup 1987-1988 379 6.2
    chrysler cordoba 1975-1979 318 5.2
    chrysler lebaron 1977-1979 318 5.2
    chrysler 300 1959-1971 413 6.8
    chrysler imperial 1959-1975 413 6.8
    chrysler town & country 1959-1979 413 6.8
    chrysler new yorker 1959-1980 413 6.8
    chrysler newport 1959-1980 413 6.8
    dodge a100 1967 273 4.5
    dodge aspen 1976-1978 318 5.2
    dodge b100 van 1974-1978 360 5.9
    dodge b200 van 1974-1978 440 7.2
    dodge b300 van 1975-1978 318 5.2
    dodge cb300 1975-1978 318 5.2
    dodge challenger 1970-1974 318 5.2
    dodge charger 1967-1968 273 4.5
    dodge charger 1969-1978 383 6.3
    dodge coronet 1957-1968 230 3.8
    dodge coronet 1969-1976 383 6.3
    dodge d100 pickup 1968-1978 383 6.3
    dodge d150 pickup 1977-1978 318 5.2
    dodge d200 pickup 1968 383 6.3
    dodge d200 pickup 1969-1978 383 6.3
    dodge d300 pickup 1968-1978 383 6.3
    dodge d450 pickup 1978 360 5.9
    dodge dart 1968-1976 273 4.5
    dodge diplomat 1978 318 5.2
    dodge m300 1974 440 7.2
    dodge m350 1974 318 5.2
    dodge magnum 1978 318 5.2
    dodge magnum 1978 400 6.6
    dodge monaco 1967-1978 426 7.0
    dodge polara 1967-1973 426 7.0
    dodge ramcharger 1974-1978 440 7.2
    dodge royal monaco 1975-1977 360 5.9
    dodge truck 1958-1959 230 3.8
    dodge w100 pickup 1968-1977 383 6.3
    dodge w150 pickup 1978 318 5.2
    dodge w150 pickup 1978 360 5.9
    dodge w150 pickup 1978 400 6.6
    dodge w150 pickup 1978 440 7.2
    dodge w200 pickup 1976-1978 318 5.2
    dodge w200 pickup 1975-1978 360 5.9
    dodge w200 pickup 1969-1970 383 6.3
    dodge w200 pickup 19761978 400 6.6
    dodge w200 pickup 1974 440 7.2
    dodge w200 pickup 1978 440 7.2
    dodge w300 pickup 1976-1978 318 5.2
    dodge w300 pickup 1975-1978 360 5.9
    dodge w300 pickup 1968-1969 383 6.3
    dodge w300 pickup 1976-1978 400 6.6
    dodge w300 pickup 1978 440 7.2
    dodge wayfarer 1950 230 3.8
    ford club 1955-1964 223 3.7
    ford country sedan 1964-1967 200 3.3
    ford country sedan 1954-1964 223 3.7
    ford country sedan 1954 256 4.2
    ford country sedan 1956-1957 272 4.5
    ford country sedan 1959-1962 292 4.8
    ford country sedan 1966-1967 352 5.8
    ford country sedan 1961-1966 390 6.4
    ford country sedan 1964-1966 427 7.0
    ford country squire 1964-1967 200 3.3
    ford country squire 1954-1964 223 3.7
    ford country squire 1954 239 3.9
    ford country squire 1954 256 4.2
    ford country squire 1956-1957 272 4.5
    ford country squire 1959-1962 292 4.8
    ford country squire 1965-1967 352 5.8
    ford country squire 1963-1964 390 6.4
    ford country squire 1964 427 7.0
    ford country squire 1966 427 7.0
    ford courier sedan delivery 1954-1960 239 3.9
    ford crestline 1954 223 3.7
    ford custom 1964 223 3.7
    ford custom 1966-1967 352 5.8
    ford custom 1964 390 6.4
    ford custom 1966 427 7.0
    ford custom 300 1959 223 3.7
    ford custom 300 1958-1959 292 4.8
    ford customline 1954-1956 239 3.9
    ford del rio wagon 1957-1958 223 3.7
    ford f series 1954-1959 239 3.9
    ford f-100 pickup 1962-1964 223 3.7
    ford f-100 pickup 1961-1964 292 4.8
    ford f-100 pickup 1966-1967 352 5.8
    ford f-250 pickup 1962-1964 223 3.7
    ford f-250 pickup 1960-1964 292 4.8
    ford f-250 pickup 1967 352 5.8
    ford f-350 pickup 1961-1964 223 3.7
    ford f-350 pickup 1960-1964 292 4.8
    ford f-350 pickup 1966-1967 352 5.8
    ford fairlane 1966-1968 200 3.3
    ford fairlane 1956-1962 223 3.7
    ford fairlane 1956-1957 272 4.5
    ford fairlane 1959-1961 292 4.8
    ford fairlane 1964 390 6.4
    ford fairlane 1966 390 6.4
    ford fairlane 1965-1966 427 7.0
    ford falcon 1964-1968 200 3.3
    ford falcon sedan delivery 1965 200 3.3
    ford ford 300 1963 223 3.7
    ford galaxie 1959-1964 223 3.7
    ford galaxie 1960-1962 292 4.8
    ford galaxie 1965-1967 352 5.8
    ford galaxie 1963-1964 390 6.4
    ford galaxie 1966 427 7.0
    ford galaxie 1966 428 7.0
    ford ltd 1967 352 5.8
    ford mainline 1954-1956 239 3.9
    ford mustang 1965-1968 200 3.3
    ford park lane wagon 1956 223 3.7
    ford ranch wagon 1966-1967 200 3.3
    ford ranch wagon 1954-1964 223 3.7
    ford ranch wagon 1954 256 4.2
    ford ranch wagon 1956-1957 272 4.5
    ford ranch wagon 1959-1962 292 4.8
    ford ranch wagon 1965-1967 352 5.8
    ford ranch wagon 1963-1966 390 6.4
    ford ranch wagon 1964 427 7.0
    ford ranch wagon 1966 427 7.0
    ford ranchero 1965-1968 200 3.3
    ford ranchero 1957-1959 223 3.7
    ford ranchero 1958-1959 292 4.8
    ford skyliner 1954-1959 239 3.9
    ford starliner 1960-1981 292 4.8
    ford sunliner 1954-1961 223 3.7
    ford sunliner 1963-1964 223 3.7
    ford sunliner 1954 239 3.9
    ford sunliner 1954 256 4.2
    ford sunliner 1956-1957 272 4.5
    ford sunliner 1959-1962 292 4.8
    ford sunliner 1963-1964 390 6.4
    ford thunderbird 1956-1958 292 4.8
    ford thunderbird 1963-1966 390 6.4
    ford thunderbird 1963-1966 427 7.0
    ford victoria 1954-1964 223 3.7
    ford victoria 1954 239 3.9
    ford victoria 1954 256 4.2
    ford victoria 1956-1957 272 4.5
    ford victoria 1959-1962 292 4.8
    ford victoria 1964 390 6.4
    gmc g25/g2500 van 1984-1993 379 6.2
    gmc g35/g3500 van 1984-1993 379 6.2
    gmc p25/p2500 van 1983-1988 379 6.2
    gmc p35/p3500 van 1983-1988 379 6.2
    gmc r1500 suburban 1988-1992 379 6.2
    gmc r2500 pickup 1987-1989 379 6.2
    gmc r2500 suburban 1988-1991 379 6.2
    gmc r3500 pickup 1988-1991 379 6.2
    gmc v1500 suburban 1988-1991 379 6.2
    gmc v2500 pickup 1987 379 6.2
    gmc v2500 suburban 1988-1991 379 6.2
    gmc v3500 pickup 1988-1991 379 6.2
    mercury breezeway 1966 390 6.4
    mercury colony park 1961-1962 292 4.8
    mercury colony park 1962 352 5.8
    mercury colony park 1963-1966 390 6.4
    mercury colony park 1966 410 6.7
    mercury colony park 1966 427 7.0
    mercury colony park 1959 430 7.0
    mercury comet 1966 427 7.0
    mercury commuter 1961 223 3.7
    mercury commuter 1957 312 5.1
    mercury commuter 1961 352 5.8
    mercury commuter 1961-1966 390 6.4
    mercury commuter 1966 427 7.0
    mercury custom 1954 256 4.2
    mercury custom 1955 292 4.8
    mercury custom 1956 312 5.1
    mercury marauder 1964-1966 390 6.4
    mercury mercury s-55 1966 390 6.4
    mercury meteor 1961 292 4.8
    mercury meteor 1961 352 5.8
    mercury meteor 1961 390 6.4
    mercury montclair 1956 312 5.1
    mercury montclair 1957-1966 312 5.1
    mercury monterey 1954 256 4.2
    mercury monterey 1955 292 4.8
    mercury monterey 1961-1962 292 4.8
    mercury monterey 1957 312 5.1
    mercury monterey 1961-1962 352 5.8
    mercury monterey 1963-1966 390 6.4
    mercury monterey 1966 410 6.7
    mercury monterey 1966 427 7
    mercury park lane 1965-1966 390 6.4
    mercury park lane 1966 427 7
    mercury park lane 1959 430 7
    mercury voyager 1959 430 7
    plymouth barracuda 1965-1974 273 4.5
    plymouth belvedere 1963-1970 318 5.2
    plymouth cuda 1970-1974 340 5.6
    plymouth deluxe 1949-1950 218 3.6
    plymouth fury 1965-1978 273 4.5
    plymouth fury i 1968-1974 383 6.3
    plymouth fury ii 1968-1974 383 6.3
    plymouth fury iii 1968-1974 383 6.3
    plymouth gran fury 1972-1977 440 7.2
    plymouth gtx 1967 440 7.2
    plymouth pb100 van 1976-1978 318 5.2
    plymouth pb200 van 1975-1978 360 5.9
    plymouth pb300 van 1975-1978 360 5.9
    plymouth roadrunner 1968-1975 383 6.3
    plymouth satellite 1965-1974 318 5.2
    plymouth savoy 1963-1964 318 5.2
    plymouth scamp 1972-1983 318 5.2
    plymouth trailduster 1976-1978 318 5.2
    plymouth trailduster 1976-1978 360 5.9
    plymouth trailduster 1977-1978 400 6.6
    plymouth trailduster 1974 440 7.2
    plymouth vip 1967 440 7.2
    Visit product page
  • Robertshaw 370-160 series hi flow balanced sleeve thermostat
    Quick shop

    The Robertshaw 370-160 series is back ! Fits Mopar, (some) Ford, Lincoln, Mercury, AMC L6 Buick Nailheads and IHC blocks

    Why Robertshaw? Because we make a hi flow pump and its unique three port construction or "balanced sleeve" design equalizes the system pressures above and below the thermostat’s moving valve. Therefore the thermostat is pressure balanced and will respond to system temperatures only. No other thermostat does this.

    Other Features of a Robert Shaw Thermostat:

    1) Stress-free construction. Robertshaw makes the thermostat's strut assembly from brass, not stainless steel, because brass can be bradded to the housing with heat instead of sledge hammer-like stress. This technique permits two brads per strut. Other manufacturers forcefully attach the struts to the housing with intense, metal-weakening pressure on the struts, binding each strut in only one spot.

    2) The Power Pill®. This is the heart of a Robertshaw thermostat. It detects minute changes in the temperature of the coolant, and quickly activates a precision-engineered stem or piston to open and close the thermostat valve.

    3) One-piece bypass poppet. With other thermostats, the bypass valve stem is welded on. The weld tends to fail under stress. To eliminate this problem, Robertshaw manufactures the entire copper cup and bypass stem from a single piece of metal.

    4) Short-stroke piston. In conventional thermostats, the piston must make a large stroke to open the thermostat far enough for adequate coolant flow. But the long stroke compromises durability. Robertshaw engineers achieved a shorter stroke with a uniquely-designed flange and poppet. This design increases the longevity of the thermostat, yet still allows adequate coolant circulation.

    5) Contoured strut. Making the strut assembly from brass instead of steel provides another benefit: brass, being more malleable than steel, can be precisely formed to maximize coolant flow.

    6) Uniform quality. Robertshaw builds all thermostats to OEM standards -- so your replacement thermostat is identical to those used in new Fords, Chryslers, and other cars. The Power Pill At the heart of a Robertshaw thermostat is the power pill. Its job: to detect minute changes in the temperature of the coolant, and to quickly activate a precision-engineered piston that opens and closes the thermostat valve. Compared to the thermal elements in some thermostats, Robertshaw's Power Pill® has major advantages:

    1) Rapid response. The Power Pill's piston is activated by a temperature-sensitive mixture of metallic powder and wax. Some thermostats use an all-wax charge, which responds slowly to temperature changes. Other brands mix copper powder with the wax for faster response, but the copper quickly separates from the wax. Robertshaw developed a process to maintain suspension of the copper powder in the wax, so the fast response doesn't deteriorate and the thermostat will not "stick-open" to cause the engine to run cool.

    2) Reliable performance. Most manufacturers use a one-piece rubber diaphragm to seal the charge and drive the piston. If the rubber part ruptures, the thermostat fails. Robertshaw uses two separate parts: a diaphragm to seal the wax, and a stem seat or plug that drives the piston. Rubber material for each part is formulated especially to meet each part's unique requirements. Wear or damage to the stem seat still allows the thermostat to operate satisfactorily.

    3) Precise performance. Every Robertshaw Power Pill is calibrated to bring the thermostat's start-to-open temperature within strict tolerances.

    Make Model Year CID Liters
    american motors super six, rambler, american,   1961-1962 196 3.2
    american motors rambler 1959-1960 196 3.2
    american motors american 1959-1968 196 3.2
    american motors rebel 1959-1970 250 4.1
    buick various 1954-1956 264 4.3
    buick special 1957-1961 364
    5.9
    buick electra gran sport , invicta, lesabre, riviera, skylark wiildcat 1959-1966 401 6.6
    buick electra gran sport , invicta, lesabre, riviera, wiildcat 1963-1966 425 7.0
    buick century roadmaster, skylark, super 1953-1956 322 5.3
    cadillac deville. eldorado  1953-1962 331 5.4

    cadillac series 60 fleetwood 1950-1964 331 5.4
    cadillac series 61 1950-1951 331 5.4
    cadillac series 62 1952-1962 331 5.4
    cadillac series 70 fleetwood eldorado 1958-1962 365 6.0
    chevrolet g20 van 1983-1993 379 6.2
    chevrolet g30 van 1983-1993 379 6.2
    chevrolet k10 pickup 1982-1986 379 6.2
    chevrolet k10 suburban 1982-1986 379 6.2
    chevrolet p20 van 1982-1989 379 6.2
    chevrolet p30 van 1982-1993 379 6.2
    chevrolet r10 pickup 1987 379 6.2
    chevrolet r10 suburban 1987-1988 379 6.2
    chevrolet r20 pickup 1987-1988 379 6.2
    chevrolet r20 suburban 1987-1988 379 6.2
    chevrolet r30 pickup 1987-1988 379 6.2
    chevrolet v10 pickup 1987    
    chevrolet v10 suburban 1987-1988 379 6.2
    chevrolet v20 pickup 1987 379 6.2
    chevrolet v20 suburban 1987-1988 379 6.2
    chevrolet v30 pickup 1987-1988 379 6.2
    chrysler cordoba 1975-1979 318 5.2
    chrysler lebaron 1977-1979 318 5.2
    chrysler 300 1959-1971 413 6.8
    chrysler imperial 1959-1975 413 6.8
    chrysler town & country 1959-1979 413 6.8
    chrysler new yorker 1959-1980 413 6.8
    chrysler newport 1959-1980 413 6.8
    dodge a100 1967 273 4.5
    dodge aspen 1976-1978 318 5.2
    dodge b100 van 1974-1978 360 5.9
    dodge b200 van 1974-1978 440 7.2
    dodge b300 van 1975-1978 318 5.2
    dodge cb300 1975-1978 318 5.2
    dodge challenger 1970-1974 318 5.2
    dodge charger 1967-1968 273 4.5
    dodge charger 1969-1978 383 6.3
    dodge coronet 1957-1968 230 3.8
    dodge coronet 1969-1976 383 6.3
    dodge d100 pickup 1968-1978 383 6.3
    dodge d150 pickup 1977-1978 318 5.2
    dodge d200 pickup 1968 383 6.3
    dodge d200 pickup 1969-1978 383 6.3
    dodge d300 pickup 1968-1978 383 6.3
    dodge d450 pickup 1978 360 5.9
    dodge dart 1968-1976 273 4.5
    dodge diplomat 1978 318 5.2
    dodge m300 1974 440 7.2
    dodge m350 1974 318 5.2
    dodge magnum 1978 318 5.2
    dodge magnum 1978 400 6.6
    dodge monaco 1967-1978 426 7.0
    dodge polara 1967-1973 426 7.0
    dodge ramcharger 1974-1978 440 7.2
    dodge royal monaco 1975-1977 360 5.9
    dodge truck 1958-1959 230 3.8
    dodge w100 pickup 1968-1977 383 6.3
    dodge w150 pickup 1978 318 5.2
    dodge w150 pickup 1978 360 5.9
    dodge w150 pickup 1978 400 6.6
    dodge w150 pickup 1978 440 7.2
    dodge w200 pickup 1976-1978 318 5.2
    dodge w200 pickup 1975-1978 360 5.9
    dodge w200 pickup 1969-1970 383 6.3
    dodge w200 pickup 19761978 400 6.6
    dodge w200 pickup 1974 440 7.2
    dodge w200 pickup 1978 440 7.2
    dodge w300 pickup 1976-1978 318 5.2
    dodge w300 pickup 1975-1978 360 5.9
    dodge w300 pickup 1968-1969 383 6.3
    dodge w300 pickup 1976-1978 400 6.6
    dodge w300 pickup 1978 440 7.2
    dodge wayfarer 1950 230 3.8
    ford club 1955-1964 223 3.7
    ford country sedan 1964-1967 200 3.3
    ford country sedan 1954-1964 223 3.7
    ford country sedan 1954 256 4.2
    ford country sedan 1956-1957 272 4.5
    ford country sedan 1959-1962 292 4.8
    ford country sedan 1966-1967 352 5.8
    ford country sedan 1963-1966 390 6.4
    ford country sedan 1964-1966 427 7.0
    ford country squire 1964-1967 200 3.3
    ford country squire 1954-1964 223 3.7
    ford country squire 1954 239 3.9
    ford country squire 1954 256 4.2
    ford country squire 1956-1957 272 4.5
    ford country squire 1959-1962 292 4.8
    ford country squire 1965-1967 352 5.8
    ford country squire 1963-1964 390 6.4
    ford country squire 1964 427 7.0
    ford country squire 1966 427 7.0
    ford courier sedan delivery 1954-1960 239 3.9
    ford crestline 1954 223 3.7
    ford custom 1964 223 3.7
    ford custom 1966-1967 352 5.8
    ford custom 1964 390 6.4
    ford custom 1966 427 7.0
    ford custom 300 1959 223 3.7
    ford custom 300 1958-1959 292 4.8
    ford customline 1954-1956 239 3.9
    ford del rio wagon 1957-1958 223 3.7
    ford f series 1954-1959 239 3.9
    ford f-100 pickup 1962-1964 223 3.7
    ford f-100 pickup 1961-1964 292 4.8
    ford f-100 pickup 1966-1967 352 5.8
    ford f-250 pickup 1962-1964 223 3.7
    ford f-250 pickup 1960-1964 292 4.8
    ford f-250 pickup 1967 352 5.8
    ford f-350 pickup 1961-1964 223 3.7
    ford f-350 pickup 1960-1964 292 4.8
    ford f-350 pickup 1966-1967 352 5.8
    ford fairlane 1966-1968 200 3.3
    ford fairlane 1956-1962 223 3.7
    ford fairlane 1956-1957 272 4.5
    ford fairlane 1959-1961 292 4.8
    ford fairlane 1964 390 6.4
    ford fairlane 1966 390 6.4
    ford fairlane 1965-1966 427 7.0
    ford falcon 1964-1968 200 3.3
    ford falcon sedan delivery 1965 200 3.3
    ford ford 300 1963 223 3.7
    ford galaxie 1959-1964 223 3.7
    ford galaxie 1960-1962 292 4.8
    ford galaxie 1965-1967 352 5.8
    ford galaxie 1963-1964 390 6.4
    ford galaxie 1966 427 7.0
    ford galaxie 1966 428 7.0
    ford ltd 1967 352 5.8
    ford mainline 1954-1956 239 3.9
    ford mustang 1965-1968 200 3.3
    ford park lane wagon 1956 223 3.7
    ford ranch wagon 1966-1967 200 3.3
    ford ranch wagon 1954-1964 223 3.7
    ford ranch wagon 1954 256 4.2
    ford ranch wagon 1956-1957 272 4.5
    ford ranch wagon 1959-1962 292 4.8
    ford ranch wagon 1965-1967 352 5.8
    ford ranch wagon 1963-1966 390 6.4
    ford ranch wagon 1964 427 7.0
    ford ranch wagon 1966 427 7.0
    ford ranchero 1965-1968 200 3.3
    ford ranchero 1957-1959 223 3.7
    ford ranchero 1958-1959 292 4.8
    ford skyliner 1954-1959 239 3.9
    ford starliner 1960-1981 292 4.8
    ford sunliner 1954-1961 223 3.7
    ford sunliner 1963-1964 223 3.7
    ford sunliner 1954 239 3.9
    ford sunliner 1954 256 4.2
    ford sunliner 1956-1957 272 4.5
    ford sunliner 1959-1962 292 4.8
    ford sunliner 1963-1964 390 6.4
    ford thunderbird 1956-1958 292 4.8
    ford thunderbird 1963-1966 390 6.4
    ford thunderbird 1963-1966 427 7.0
    ford victoria 1954-1964 223 3.7
    ford victoria 1954 239 3.9
    ford victoria 1954 256 4.2
    ford victoria 1956-1957 272 4.5
    ford victoria 1959-1962 292 4.8
    ford victoria 1964 390 6.4
    gmc g25/g2500 van 1984-1993 379 6.2
    gmc g35/g3500 van 1984-1993 379 6.2
    gmc p25/p2500 van 1983-1988 379 6.2
    gmc p35/p3500 van 1983-1988 379 6.2
    gmc r1500 suburban 1988-1992 379 6.2
    gmc r2500 pickup 1987-1989 379 6.2
    gmc r2500 suburban 1988-1991 379 6.2
    gmc r3500 pickup 1988-1991 379 6.2
    gmc v1500 suburban 1988-1991 379 6.2
    gmc v2500 pickup 1987 379 6.2
    gmc v2500 suburban 1988-1991 379 6.2
    IHC scout et al 1950s-1970s 266,304,345
    gmc v3500 pickup 1988-1991 379 6.2
    mercury breezeway 1966 390 6.4
    mercury colony park 1961-1962 292 4.8
    mercury colony park 1962 352 5.8
    mercury colony park 1963-1966 390 6.4
    mercury colony park 1966 410 6.7
    mercury colony park 1966 427 7.0
    mercury colony park 1959 430 7.0
    mercury comet 1966 427 7.0
    mercury commuter 1961 223 3.7
    mercury commuter 1957 312 5.1
    mercury commuter 1961 352 5.8
    mercury commuter 1962-1966 390 6.4
    mercury commuter 1966 427 7.0
    mercury custom 1954 256 4.2
    mercury custom 1955 292 4.8
    mercury custom 1956 312 5.1
    mercury marauder 1964-1966 390 6.4
    mercury mercury s-55 1966 390 6.4
    mercury meteor 1961 292 4.8
    mercury meteor 1961 352 5.8
    mercury meteor 1961 390 6.4
    mercury montclair 1956 312 5.1
    mercury montclair 1957-1966 312 5.1
    mercury monterey 1954 256 4.2
    mercury monterey 1955 292 4.8
    mercury monterey 1961-1962 292 4.8
    mercury monterey 1957 312 5.1
    mercury monterey 1961-1962 352 5.8
    mercury monterey 1963-1966 390 6.4
    mercury monterey 1966 410 6.7
    mercury monterey 1966 427 7
    mercury park lane 1965-1966 390 6.4
    mercury park lane 1966 427 7
    mercury park lane 1959 430 7
    mercury voyager 1959 430 7
    plymouth barracuda 1965-1974 273 4.5
    plymouth belvedere 1963-1970 318 5.2
    plymouth cuda 1970-1974 340 5.6
    plymouth deluxe 1949-1950 218 3.6
    plymouth fury 1965-1978 273 4.5
    plymouth fury i 1968-1974 383 6.3
    plymouth fury ii 1968-1974 383 6.3
    plymouth fury iii 1968-1974 383 6.3
    plymouth gran fury 1972-1977 440 7.2
    plymouth gtx 1967