Save Up to 15% on Back to School Auto Parts
24/7 Customer service
USD
Add your vehicle
Address
Login
Cart
Item
$0.00
A-Premium Back to School Car Deals Up to 15% OFFA-Premium Back to School Car Deals Up to 15% OFF
Add your vehicle to ensure fitment/Choose a yearRequired Fields
Select a different vehicle
Make/Model
VIN
Save

Geo Thermostat

15 items

Upgrade your vehicle's thermostat with A-Premium's high-quality options. Choose reliability and durability for a smoother ride.

  • All filters
  • Sort By
  • Year
  • Model
  • Price
  • Brand
  • Material
  • Warranty
A-Premium APTHE018 Engine Coolant ThermostatA-Premium APTHE018 Engine Coolant Thermostat
A-Premium®Part # APTHE018
A-Premium APTHE018 Engine Coolant Thermostat
4.683 Reviews
$17.99
Edit ZIP code
2-year warranty
90 days free return
Fits 1985 - 1988 Chevrolet Nova, 2008 - 2009 Ford F-650, 2008 - 2009 Ford F-750, 1998 - 1998 Ford F-800, 1998 - 1998 Ford F-800 LPO, 1989 - 1997 Geo Prizm, 1993 - 1997 Geo Prizm, 1995 - 1995 Nissan 200SX, 1997 - 1998 Nissan 200SX, 1991 - 1993 Nissan NX, 1989 - 1990 Nissan Pulsar NX, 1989 - 1999 Nissan Sentra, 1996 - 1997 Nissan Sentra, 1984 - 1986 Toyota Camry, 1983 - 1991 Toyota Camry, 1992 - 2001 Toyota Camry, 1990 - 1993 Toyota Celica, 1994 - 1997 Toyota Celica, 1986 - 1989 Toyota Celica, 1992 - 1999 Toyota Celica
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Geo
Item LocatedUnited States
Quantity1
MaterialMetal
ConditionNew
item #1005UU8S
Show less
A-Premium APTHE017 Engine Coolant Thermostat
A-Premium®Part # APTHE017
A-Premium APTHE017 Engine Coolant Thermostat
4.683 Reviews
$17.99
Edit ZIP code
2-year warranty
90 days free return
Fits 1985 - 1988 Chevrolet Nova, 2008 - 2009 Ford F-650, 2008 - 2009 Ford F-750, 1998 - 1998 Ford F-800, 1998 - 1998 Ford F-800 LPO, 1989 - 1997 Geo Prizm, 1993 - 1997 Geo Prizm, 1995 - 1995 Nissan 200SX, 1997 - 1998 Nissan 200SX, 1991 - 1993 Nissan NX, 1989 - 1990 Nissan Pulsar NX, 1989 - 1999 Nissan Sentra, 1996 - 1997 Nissan Sentra, 1984 - 1986 Toyota Camry, 1983 - 1991 Toyota Camry, 1992 - 2001 Toyota Camry, 1990 - 1993 Toyota Celica, 1994 - 1997 Toyota Celica, 1986 - 1989 Toyota Celica, 1992 - 1999 Toyota Celica
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Geo
Item LocatedUnited States
Quantity1
MaterialMetal
ConditionNew
item #1005USAT
Show less
Beck/Arnley 143-0686 Engine Coolant Thermostat
Beck/ArnleyPart # 143-0686
Beck/Arnley 143-0686 Engine Coolant Thermostat
51 Reviews
$21.99
Edit ZIP code
3-year warranty
90 days free return
Fits 1982-1982 Chevrolet LUV, 1985-1988 Chevrolet Spectrum, 1989-1989 Geo Spectrum, 1990-1991 Geo Storm, 1992-1993 Geo Storm, 1994-1996 Honda Passport, 1981-1982 Isuzu Pickup, 1981-1984 Isuzu I-Mark, 1983-1987 Isuzu Pickup, 1983-1991 Isuzu Impulse, 1984-1984 Isuzu Trooper, 1985-1985 Isuzu I-Mark, 1985-1985 Isuzu Trooper, 1986-1987 Isuzu Trooper, 1986-1989 Isuzu I-Mark, 1988-1988 Isuzu Trooper, 1988-1990 Isuzu Pickup, 1988-1995 Isuzu Pickup, 1988-1995 Isuzu Pickup, 1989-1991 Isuzu Trooper
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Geo
Item LocatedUnited States
QuantityOne Set
Part interchange
143-0686
item #1000XHZN
Show less
Beck/Arnley 143-0684 Engine Coolant Thermostat
Beck/ArnleyPart # 143-0684
Beck/Arnley 143-0684 Engine Coolant Thermostat
51 Reviews
$20.99
Edit ZIP code
3-year warranty
90 days free return
Fits 1982-1982 Chevrolet LUV, 1985-1988 Chevrolet Spectrum, 1989-1989 Geo Spectrum, 1990-1991 Geo Storm, 1992-1993 Geo Storm, 1994-1996 Honda Passport, 1981-1982 Isuzu Pickup, 1981-1984 Isuzu I-Mark, 1983-1987 Isuzu Pickup, 1983-1991 Isuzu Impulse, 1984-1984 Isuzu Trooper, 1985-1985 Isuzu I-Mark, 1985-1985 Isuzu Trooper, 1986-1987 Isuzu Trooper, 1986-1989 Isuzu I-Mark, 1988-1988 Isuzu Trooper, 1988-1990 Isuzu Pickup, 1989-1991 Isuzu Trooper, 1989-1994 Isuzu Amigo, 1991-1991 Isuzu Stylus
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Geo
Item LocatedUnited States
Quantity1
Part interchange
143-0684
item #1000XKL4
Show less
Beck/Arnley 143-0694 Engine Coolant Thermostat
Beck/ArnleyPart # 143-0694
Beck/Arnley 143-0694 Engine Coolant Thermostat
51 Reviews
$21.99
Edit ZIP code
3-year warranty
90 days free return
Fits 1998-2000 Chevrolet Metro, 1989-1993 Geo Metro, 1995-1997 Geo Metro, 1991-1992 Isuzu Rodeo, 1991-1994 Isuzu Pickup, 1984-1991 Nissan Micra, 1987-1991 Subaru Justy, 1989-1991 Suzuki Swift, 1992-1994 Suzuki Swift, 1995-1998 Suzuki Esteem, 1995-1999 Suzuki Swift, 1999-2000 Suzuki Esteem
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Geo
Item LocatedUnited States
QuantityOne Set
Part interchange
143-0694
item #1000XLD4
Show less
Beck/Arnley 143-0685 Engine Coolant Thermostat
Beck/ArnleyPart # 143-0685
Beck/Arnley 143-0685 Engine Coolant Thermostat
51 Reviews
$19.99
Edit ZIP code
3-year warranty
90 days free return
Fits 1982-1982 Chevrolet LUV, 1985-1988 Chevrolet Spectrum, 1989-1989 Geo Spectrum, 1990-1991 Geo Storm, 1992-1993 Geo Storm, 1994-1996 Honda Passport, 1981-1982 Isuzu Pickup, 1981-1984 Isuzu I-Mark, 1983-1987 Isuzu Pickup, 1983-1991 Isuzu Impulse, 1984-1984 Isuzu Trooper, 1985-1985 Isuzu I-Mark, 1985-1985 Isuzu Trooper, 1986-1987 Isuzu Trooper, 1986-1989 Isuzu I-Mark, 1988-1988 Isuzu Trooper, 1988-1990 Isuzu Pickup, 1988-1995 Isuzu Pickup, 1988-1995 Isuzu Pickup, 1989-1991 Isuzu Trooper
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Geo
Item LocatedUnited States
Quantity1
Part interchange
143-0685
item #1000XH1H
Show less
Beck/Arnley 143-0688 Engine Coolant Thermostat
Beck/ArnleyPart # 143-0688
Beck/Arnley 143-0688 Engine Coolant Thermostat
51 Reviews
$27.99
Edit ZIP code
3-year warranty
90 days free return
Fits 1998-1998 Chevrolet Tracker, 1999-1999 Chevrolet Tracker, 1999-1999 Chevrolet Tracker, 1999-1999 Chevrolet Tracker, 1982-1985 Chrysler LeBaron, 1983-1984 Chrysler E Class, 1983-1984 Chrysler Executive Sedan, 1983-1985 Chrysler New Yorker, 1985-1985 Chrysler Executive Limousine, 1987-1989 Chrysler Conquest, 1988-1989 Chrysler New Yorker, 1989-1990 Chrysler Dynasty, 1990-1995 Chrysler LeBaron, 1971-1978 Dodge Colt, 1978-1983 Dodge Challenger, 1979-1980 Dodge Colt, 1979-1981 Dodge D50, 1979-1984 Dodge Colt, 1981-1985 Dodge Aries, 1982-1983 Dodge 400
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Geo
Item LocatedUnited States
Quantity1
Part interchange
143-0688
item #1000XGE3
Show less
Beck/Arnley 143-0689 Engine Coolant Thermostat
Beck/ArnleyPart # 143-0689
Beck/Arnley 143-0689 Engine Coolant Thermostat
51 Reviews
$23.99
Edit ZIP code
3-year warranty
90 days free return
Fits 1998-1998 Chevrolet Tracker, 1999-1999 Chevrolet Tracker, 1999-1999 Chevrolet Tracker, 1999-1999 Chevrolet Tracker, 1982-1985 Chrysler LeBaron, 1983-1984 Chrysler E Class, 1983-1984 Chrysler Executive Sedan, 1983-1985 Chrysler New Yorker, 1985-1985 Chrysler Executive Limousine, 1987-1989 Chrysler Conquest, 1988-1989 Chrysler New Yorker, 1989-1990 Chrysler Dynasty, 1971-1978 Dodge Colt, 1978-1983 Dodge Challenger, 1979-1980 Dodge Colt, 1979-1981 Dodge D50, 1979-1984 Dodge Colt, 1981-1985 Dodge Aries, 1982-1983 Dodge 400, 1983-1983 Dodge Power Ram 50
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Geo
Item LocatedUnited States
Quantity1
Part interchange
143-0689
item #1000XHG9
Show less
Beck/Arnley 143-0728 Engine Coolant Thermostat
Beck/ArnleyPart # 143-0728
Beck/Arnley 143-0728 Engine Coolant Thermostat
51 Reviews
$30.99
Edit ZIP code
3-year warranty
90 days free return
Fits 1985-1988 Chevrolet Nova, 1989-1997 Geo Prizm, 1989-1989 Nissan Pulsar NX, 1989-1990 Nissan Sentra, 1990-1990 Nissan Pulsar NX, 1991-1993 Nissan NX, 1991-1994 Nissan Sentra, 1995-1995 Nissan Sentra, 1995-1998 Nissan 200SX, 1996-1999 Nissan Sentra, 1980-1997 Toyota Tercel, 1983-1985 Toyota Camry, 1983-1997 Toyota Corolla, 1984-1989 Toyota Van, 1985-1989 Toyota MR2, 1986-1986 Toyota Camry, 1986-1986 Toyota Celica, 1987-1987 Toyota Camry, 1987-1989 Toyota Celica, 1988-1991 Toyota Camry
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Geo
Item LocatedUnited States
QuantityOne Set
Part interchange
143-0728
item #1000XLL2
Show less
Beck/Arnley 143-0687 Engine Coolant Thermostat
Beck/ArnleyPart # 143-0687
Beck/Arnley 143-0687 Engine Coolant Thermostat
51 Reviews
$22.99
Edit ZIP code
3-year warranty
90 days free return
Fits 1998-1998 Chevrolet Tracker, 1999-1999 Chevrolet Tracker, 1999-1999 Chevrolet Tracker, 1999-1999 Chevrolet Tracker, 1982-1985 Chrysler LeBaron, 1983-1984 Chrysler E Class, 1983-1984 Chrysler Executive Sedan, 1983-1985 Chrysler New Yorker, 1985-1985 Chrysler Executive Limousine, 1987-1989 Chrysler Conquest, 1988-1989 Chrysler New Yorker, 1989-1990 Chrysler Dynasty, 1971-1978 Dodge Colt, 1978-1983 Dodge Challenger, 1979-1980 Dodge Colt, 1979-1981 Dodge D50, 1979-1983 Dodge Colt, 1981-1985 Dodge Aries, 1982-1983 Dodge 400, 1983-1983 Dodge Power Ram 50
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Geo
Item LocatedUnited States
QuantityOne Set
Part interchange
143-0687
item #1000XKVK
Show less
Beck/Arnley 143-0697 Engine Coolant Thermostat
Beck/ArnleyPart # 143-0697
Beck/Arnley 143-0697 Engine Coolant Thermostat
51 Reviews
$23.99
Edit ZIP code
3-year warranty
90 days free return
Fits 1985-1988 Chevrolet Nova, 1989-1997 Geo Prizm, 1989-1989 Nissan Pulsar NX, 1989-1990 Nissan Sentra, 1990-1990 Nissan Pulsar NX, 1991-1993 Nissan NX, 1991-1994 Nissan Sentra, 1995-1995 Nissan Sentra, 1995-1998 Nissan 200SX, 1996-1999 Nissan Sentra, 1980-1999 Toyota Tercel, 1983-1985 Toyota Camry, 1983-1997 Toyota Corolla, 1984-1989 Toyota Van, 1985-1989 Toyota MR2, 1986-1986 Toyota Camry, 1986-1986 Toyota Celica, 1987-1987 Toyota Camry, 1987-1989 Toyota Celica, 1988-1991 Toyota Camry
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Geo
Item LocatedUnited States
Quantity1
Part interchange
143-0697
item #1000XKK3
Show less
Beck/Arnley 143-0654 Engine Coolant Thermostat
Beck/ArnleyPart # 143-0654
Beck/Arnley 143-0654 Engine Coolant Thermostat
51 Reviews
$31.99
Edit ZIP code
3-year warranty
90 days free return
Fits 1985-1988 Chevrolet Nova, 1989-1997 Geo Prizm, 1989-1989 Nissan Pulsar NX, 1989-1990 Nissan Sentra, 1990-1990 Nissan Pulsar NX, 1991-1993 Nissan NX, 1991-1994 Nissan Sentra, 1995-1995 Nissan Sentra, 1995-1998 Nissan 200SX, 1996-1999 Nissan Sentra, 1980-1997 Toyota Tercel, 1983-1985 Toyota Camry, 1983-1997 Toyota Corolla, 1984-1989 Toyota Van, 1985-1989 Toyota MR2, 1986-1986 Toyota Camry, 1986-1986 Toyota Celica, 1987-1987 Toyota Camry, 1987-1989 Toyota Celica, 1988-1991 Toyota Camry
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Geo
Item LocatedUnited States
QuantityOne Set
Part interchange
143-0654
item #1000XK4S
Show less
Beck/Arnley 143-0727 Engine Coolant Thermostat
Beck/ArnleyPart # 143-0727
Beck/Arnley 143-0727 Engine Coolant Thermostat
51 Reviews
$22.99
Edit ZIP code
3-year warranty
90 days free return
Fits 1998-2000 Chevrolet Metro, 1989-1993 Geo Metro, 1995-1997 Geo Metro, 1990-1991 Isuzu Trooper, 1991-1992 Isuzu Rodeo, 1991-1994 Isuzu Pickup, 1984-1991 Nissan Micra, 1987-1991 Subaru Justy, 1989-1991 Suzuki Swift, 1992-1994 Suzuki Swift, 1995-1998 Suzuki Esteem, 1995-2001 Suzuki Swift, 1999-2000 Suzuki Esteem
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Geo
Item LocatedUnited States
QuantityOne Set
Part interchange
143-0727
item #1000XGS4
Show less
Engine Coolant Thermostat - Mahle TX 7 88D
MahlePart # TX 7 88D
Engine Coolant Thermostat - Mahle TX 7 88D
51 Reviews
$23.99
Edit ZIP code
3-year warranty
90 days free return
Fits 1989-1991 Chevrolet Tracker, 1998-1998 Chevrolet Tracker, 1986-1986 Ford Bronco II, 1986-1990 Ford Ranger, 1987-1990 Ford Bronco II, 1990-1997 Ford Aerostar, 1990-2000 Ford Ranger, 1991-1995 Ford Explorer, 1996-2000 Ford Explorer, 1989-1997 Geo Tracker, 1991-1994 Mazda Navajo, 1994-2000 Mazda B4000, 1986-1995 Suzuki Samurai, 1989-1989 Suzuki Sidekick, 1996-1998 Suzuki X-90
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Geo
Item LocatedUnited States
Quantity1
Part interchange
TX 7 88D, RT1161, 33199S, 13959, TX788D, 201-192JV, 17600-83841, 17600-85841, 
...View more
item #1000XLX6
Show less
Engine Coolant Thermostat - Mahle TX 159 82
MahlePart # TX 159 82
Engine Coolant Thermostat - Mahle TX 159 82
51 Reviews
$24.99
Edit ZIP code
3-year warranty
90 days free return
Fits 1985-1987 Chevrolet Nova, 1993-1997 Geo Prizm, 1989-1989 Nissan Pulsar NX, 1989-1990 Nissan Sentra, 1990-1990 Nissan Pulsar NX, 1991-1993 Nissan NX, 1991-1994 Nissan Sentra, 1995-1995 Nissan Sentra, 1995-1998 Nissan 200SX, 1996-1999 Nissan Sentra, 1980-1999 Toyota Tercel, 1983-1983 Toyota Camry, 1984-1985 Toyota Camry, 1984-1985 Toyota Corolla, 1984-1989 Toyota Van, 1985-1989 Toyota MR2, 1986-1986 Toyota Camry, 1986-1986 Toyota Camry, 1986-1986 Toyota Camry, 1986-1986 Toyota Celica
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Geo
Item LocatedUnited States
Quantity1
Part interchange
TX 159 82, 21200 77A61, 21200 77A60, 33708, 131-109, 131-110, 13758, TX15982, 
...View more
item #1000XR4E
Show less

What is an engine thermostat?

 While all engines can become too hot, if your thermostat isn't working correctly, your engine's well-being is at serious risk. The engine thermostat, often simply referred to as a thermostat, regulates the engine's operating temperature within an optimal range (typically around 195 to 220 degrees Fahrenheit).

How does a car thermostat work?

As a temperature-sensitive valve within the cooling system, a car thermostat responds to changes in coolant temperature. Understanding how it works by the following breakdown steps:

  • Closed position (cold start)

Initially closed to help the engine warm up quickly.

  • Heating up

The engine generates heat during operation.

  • Opening the thermostat

A temperature-sensitive element (usually wax) causes the thermostat to open gradually.

  • Coolant flow

When open, coolant flows from the engine to the radiator.

  • Maintaining optimal temperature

Adjusts coolant flow to maintain the ideal engine temperature.

  • Temperature regulation

Continuously adjusts to prevent overheating and ensure efficient operation.

Signs of a bad thermostat

  1. Overheating: The engine becomes excessively hot due to a stuck-closed thermostat.
  2. Low or fluctuating temperature: A thermostat stuck open results in a cooler engine, affecting fuel efficiency and heating.
  3. Temperature warning light: Illuminates to indicate engine overheating due to a faulty thermostat.
  4. Poor fuel efficiency: Stuck-open thermostat reduces fuel efficiency as the engine operates less efficiently at lower temperatures.
  5. Inadequate cabin heating: Insufficient cabin heating in cold weather with a thermostat that's stuck open.
  6. Coolant leaks: Gasket or sealing issues can lead to coolant leaks.
  7. Rapid temperature fluctuations: The gauge shows rapid swings between hot and cold.
  8. Engine running hot at idle: Higher engine temperature during idle or in traffic due to restricted coolant flow.
  9. Slow or inconsistent warm-up: Longer-than-normal warm-up times, even in moderate weather.
  10. Inconsistent heater operation: This affects the performance of the vehicle's heater, causing inconsistent or inadequate heating in cold weather.

Related Blogs

Why Does Coolant Boil After You Turn the Engine Off?

Learn why coolant boils or bubbles after you turn the engine off, how heat soak affects the cooling system, and how to diagnose leaks, trapped air, cap, thermostat, fan, water pump, or head gasket problems.

Jul 29, 2026