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Thermostat

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Engine Coolant Thermostat
A-Premium®
Engine Coolant Thermostat for Subaru Outback 13-19 Forester Mitsubishi Scion 87℃
$23.99
Quantity Less than 2
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2-year warranty
90 days free return
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Vehicle: Subaru Impreza
Item LocatedUnited States
Quantity1
Part interchange
762-189, TH658787J, 1305A283, 1305A803
ConditionNew
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Engine Coolant Thermostat
A-Premium®
Engine Coolant Thermostat for Subaru Outback Forester Impreza Legacy Tribeca 60℃
$20.99
Quantity Less than 5
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2-year warranty
90 days free return
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Vehicle: Subaru Impreza
Item LocatedUnited States
Quantity1
Part interchange
294-140, 294140
ConditionNew
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Engine Coolant Thermostat
A-Premium®
Engine Coolant Thermostat for Subaru Outback Forester Impreza WRX Saab 9-2X 78℃
$22.99
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2-year warranty
90 days free return
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Vehicle: Subaru Impreza
Item LocatedUnited States
Quantity1
Part interchange
34012, THF002, 21210AA030
ConditionNew
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Engine Coolant Thermostat
A-Premium®
Engine Coolant Thermostat for Subaru Outback Forester Impreza Legacy Tribeca 77℃
$22.99
Quantity Less than 3
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2-year warranty
90 days free return
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Vehicle: Subaru Impreza
Item LocatedUnited States
Quantity1
Part interchange
294-170, 2094170, 5294170, 7294170, 33857, 33857S, TH673678J, 14147, 
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ConditionNew
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Engine Coolant Thermostat
A-Premium®
Engine Coolant Thermostat for Subaru Outback 13-19 Forester Impreza Toyota 89℃
$20.99
Quantity Less than 4
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2-year warranty
90 days free return
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Vehicle: Subaru Impreza
Item LocatedUnited States
Quantity1
Part interchange
762-192, 1430912, 78948, 21210AA181, 21210AA300, SU00300407, SU00300408, SU00304960, 
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ConditionNew
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Engine Coolant Thermostat
A-Premium®
Engine Coolant Thermostat for Subaru Outback 00-15 Forester Impreza Legacy 82℃
$23.99
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2-year warranty
90 days free return
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Vehicle: Subaru Impreza
Item LocatedUnited States
Quantity1
Part interchange
THF003, 21200AA170, 21210AA080
ConditionNew
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Beck/Arnley 143-0710 Engine Coolant Thermostat
Beck/Arnley
Beck/Arnley 143-0710 Engine Coolant Thermostat
$36.99
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3-year warranty
90 days free return
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Vehicle: Subaru Impreza
Item LocatedUnited States
Quantity1
Part interchange
143-0710
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Beck/Arnley 143-0923 Engine Coolant Thermostat
Beck/Arnley
Beck/Arnley 143-0923 Engine Coolant Thermostat
$29.99
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3-year warranty
90 days free return
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Vehicle: Subaru Impreza
Item LocatedUnited States
Quantity1
Part interchange
143-0923
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Beck/Arnley 143-0972 Engine Coolant Thermostat
Beck/Arnley
Beck/Arnley 143-0972 Engine Coolant Thermostat
$24.99
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3-year warranty
90 days free return
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Vehicle: Subaru Impreza
Item LocatedUnited States
Quantity1
Part interchange
143-0972
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Engine Coolant Thermostat - Mahle TX 143 78D
Mahle
Engine Coolant Thermostat - Mahle TX 143 78D
$28.99
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3-year warranty
90 days free return
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Vehicle: Subaru Impreza
Item LocatedUnited States
Quantity1
Part interchange
TX 143 78D, 410230.78D, 33857, 48457, TX14378D, 294-170, 21200 AA072, 21200 AA071, 
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Engine Coolant Thermostat - Upper - Mahle TX 258 55
Mahle
Engine Coolant Thermostat - Upper - Mahle TX 258 55
$30.99
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3-year warranty
90 days free return
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Vehicle: Subaru Impreza
Item LocatedUnited States
Quantity1
Installation PositionUpper
Part interchange
TX 258 55, TX 258 55, 21210 AA190
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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.