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Chevrolet Trailblazer Thermostat

12 items

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

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Engine Coolant Thermostat Housing Assembly for 2003 Chevrolet Trailblazer EXTEngine Coolant Thermostat Housing Assembly for 2003 Chevrolet Trailblazer EXT
A-Premium®Part # APTHA0109
Engine Coolant Thermostat Housing Assembly for 2003 Chevrolet Trailblazer EXT
52 Reviews
CA$42.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2003 Chevrolet Trailblazer EXT
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Chevrolet Trailblazer
Item LocatedCanada
ColorNatural
ConditionNew
item #1005DXU3
Note
Engine Coolant Thermostat Housing Assembly -- With Water Pump Casting No. 12562459, Includes 186 Fahrenheit Degree Thermostat.
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Thermostat Housing Assembly for 2003 Chevrolet Trailblazer EXT
A-Premium®Part # APTHA0128
Thermostat Housing Assembly for 2003 Chevrolet Trailblazer EXT
52 Reviews
CA$43.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2003 Chevrolet Trailblazer EXT
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Chevrolet Trailblazer
Item LocatedCanada
Quantity1
MaterialAluminum
ConditionNew
item #10027QA3
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Thermostat Housing Assembly for 2002-2006 Chevrolet Trailblazer EXT
A-Premium®Part # APTHA0084
Thermostat Housing Assembly for 2002-2006 Chevrolet Trailblazer EXT
52 Reviews
CA$30.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits Chevrolet Trailblazer EXT: 2002 2003 2004 2005 2006
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Chevrolet Trailblazer
Item LocatedCanada
Quantity1
ColorNatural
ConditionNew
item #1012YNX7
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Thermostat Housing Assembly with Thermostat for 2002-2006 Chevrolet Trailblazer EXT
A-Premium®Part # APTHA0127
Thermostat Housing Assembly with Thermostat for 2002-2006 Chevrolet Trailblazer EXT
52 Reviews
CA$40.99
CA$45.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits Chevrolet Trailblazer EXT: 2002 2003 2004 2005 2006
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Chevrolet Trailblazer
Item LocatedCanada
Quantity1
ConditionNew
item #1012ZG3K
Note
This item comes with a Cover.
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Thermostat Housing Assembly for 2006 Chevrolet Trailblazer
A-Premium®Part # APTHA0131
Thermostat Housing Assembly for 2006 Chevrolet Trailblazer
52 Reviews
CA$27.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2006 Chevrolet Trailblazer
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Chevrolet Trailblazer
Item LocatedCanada
Quantity1
ConditionNew
item #10021Q17
Note
This item comes with a Cover.
Show less
Thermostat Housing Assembly for 2007-2009 Chevrolet Trailblazer
A-Premium®Part # APTHA0203
Thermostat Housing Assembly for 2007-2009 Chevrolet Trailblazer
52 Reviews
CA$22.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Chevrolet Trailblazer
Item LocatedCanada
Quantity1
Installation PositionWater Pump
ConditionNew
item #1012ZEVV
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Thermostat Housing Assembly for 2002-2009 Chevrolet Trailblazer
A-Premium®Part # APTHA0084
Thermostat Housing Assembly for 2002-2009 Chevrolet Trailblazer
52 Reviews
CA$30.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits Chevrolet Trailblazer: 2002 2003 2004 2005 2006 2007 2008 2009
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Chevrolet Trailblazer
Item LocatedCanada
Quantity1
ColorNatural
ConditionNew
item #1012YQE7
Show less
Thermostat Housing Assembly with Thermostat for 2002-2009 Chevrolet Trailblazer
A-Premium®Part # APTHA0127
Thermostat Housing Assembly with Thermostat for 2002-2009 Chevrolet Trailblazer
52 Reviews
CA$40.99
CA$45.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits Chevrolet Trailblazer: 2002 2003 2004 2005 2006 2007 2008 2009
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Chevrolet Trailblazer
Item LocatedCanada
Quantity1
ConditionNew
item #1012ZHV2
Note
This item comes with a Cover.
Show less
Thermostat Housing Assembly for 2003-2006 Chevrolet Trailblazer EXT
A-Premium®Part # APTHA0131
Thermostat Housing Assembly for 2003-2006 Chevrolet Trailblazer EXT
52 Reviews
CA$27.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits Chevrolet Trailblazer EXT: 2003 2004 2005 2006
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Chevrolet Trailblazer
Item LocatedCanada
Quantity1
ConditionNew
item #1012W3LV
Note
This item comes with a Cover.
Show less
Thermostat Housing for 2006 Chevrolet Trailblazer
A-Premium®Part # APTHA0198
Thermostat Housing for 2006 Chevrolet Trailblazer
52 Reviews
CA$39.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2006 Chevrolet Trailblazer
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Chevrolet Trailblazer
Item LocatedUnited States
Quantity1
ColorNatural
ConditionNew
item #10152DDQ
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Engine Coolant Thermostat for 2007-2009 Chevrolet Trailblazer
A-Premium®Part # APTHE031
Engine Coolant Thermostat for 2007-2009 Chevrolet Trailblazer
52 Reviews
CA$27.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Chevrolet Trailblazer
Item LocatedUnited States
Quantity1
MaterialMetal and Rubber
ConditionNew
item #1012NL43
Show less
Thermostat Housing for 2003-2006 Chevrolet Trailblazer EXT
A-Premium®Part # APTHA0198
Thermostat Housing for 2003-2006 Chevrolet Trailblazer EXT
52 Reviews
CA$39.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits Chevrolet Trailblazer EXT: 2003 2004 2005 2006
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: Chevrolet Trailblazer
Item LocatedUnited States
Quantity1
ColorNatural
ConditionNew
item #10152HC9
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