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Four Seasons 37866 Engine Coolant Temperature Sensor
| Brand | Four Seasons 37866 |
|---|---|
| Connector Gender | Female |
| Connector Shape | Oval |
| Description | Coolant Temp Sensor |
| Fitting Thread Size | M12-1.25 |
| Meets / Exceeds OEM? | YES |
| Number of Terminals | 2 |
| Style | Coolant Temp Sensor |
| Type | Coolant Temp Sensor |
| Product line | Coolant Temp Sensor |
| Fits | Buick, Chevrolet, GMC, Isuzu, Saab, and Oldsmobile · 27 vehicles |
OE direct replacement. Meets or exceeds OEM requirements for dependable cooling-system sensing.
Oval connector. Female, 2-terminal design for a secure electrical connection.
M12-1.25 thread. Engineered for a precise threaded fit in the cooling system.
Cross-references Four Seasons 37866, Global Parts Distributors LLC 1712578 and 1712467 for the same application. See all 11.
Will it fit your vehicle?
Free return shipping if it doesn't fit.
Engine Coolant Temperature Sensor for GM Applications
Four Seasons Coolant Temp Sensor 37866 is an engine coolant temperature sensor built for direct-fit service on select GM vehicles. It uses a female oval connector, 2 terminals, and an M12-1.25 fitting thread size for the listed applications.
Compatible With 2002-2005 Chevrolet Trailblazer, 2002-2005 GMC Envoy, and related Buick, Isuzu, Saab, and Oldsmobile models, this Four Seasons coolant temp sensor 37866 meets or exceeds OEM requirements for the specified fitments.
Key Features
- Brand: Four Seasons Coolant Temp Sensor
- Part number: 37866
- Engine coolant temperature sensor for cooling system monitoring
- Female oval connector with 2 terminals
- M12-1.25 fitting thread size
- Meets or exceeds OEM specifications
- Direct-fit replacement for listed vehicle applications
Product Details
This engine coolant temperature sensor helps the vehicle’s control system read coolant temperature accurately so the engine management system can respond correctly. Four Seasons 37866 is listed for 2002-2005 Chevrolet Trailblazer, 2002-2005 GMC Envoy, 2004-2005 Buick Rainier, 2003-2005 Isuzu Ascender, 2005 Saab 9-7x, 2002-2004 Oldsmobile Bravada, 2002-2005 Chevrolet Trailblazer EXT, 2002-2005 GMC Envoy XL, and 2004-2005 GMC Envoy XUV. This part cross-references Global Parts Distributors LLC 1712578 for the same application.
Common Issues This Part May Address
- Incorrect coolant temperature readings on the dash or scan tool
- Hard starting or rough running related to temperature input errors
- Cooling fan operation that does not match engine temperature
- Check engine light concerns tied to coolant temperature sensor faults
- Fuel mixture or idle control issues caused by inaccurate coolant data
Installation Notes and Tips
Verify connector shape, terminal count, and thread size before installation. Confirm the sensor location on the engine and compare the removed part to the listed specifications for your Chevrolet Trailblazer, GMC Envoy, Buick Rainier, or other supported model. Clear diagnostic trouble codes after installation and recheck coolant temperature readings with a scan tool if available.
Quality Assurance
Four Seasons lists this coolant temp sensor as meeting or exceeding OEM requirements for the specified applications, supporting proper fit and function in the vehicles shown.
| Year | Make | Model | Liters | Cylinders | Position | Notes |
|---|---|---|---|---|---|---|
| 2005 | Buick | Rainier | 4.2L | L6 | N/A | Coolant Temp Sensor |
| 2005 | Chevrolet | Trailblazer | — | — | N/A | Coolant Temp Sensor |
| 2005 | Chevrolet | Trailblazer EXT | 4.2L | L6 | N/A | Coolant Temp Sensor |
| 2005 | GMC | Envoy | 4.2L | L6 | N/A | Coolant Temp Sensor |
| 2005 | GMC | Envoy XL | 4.2L | L6 | N/A | Coolant Temp Sensor |
| 2005 | GMC | Envoy XUV | 4.2L | L6 | N/A | Coolant Temp Sensor |
| 2005 | Isuzu | Ascender | 4.2L | L6 | N/A | Coolant Temp Sensor |
| 2005 | Saab | 9-7x | 4.2L | L6 | N/A | Coolant Temp Sensor |
| 2004 | Buick | Rainier | 4.2L | L6 | N/A | Coolant Temp Sensor |
| 2004 | Chevrolet | Trailblazer | — | — | N/A | Coolant Temp Sensor |
| 2004 | Chevrolet | Trailblazer EXT | 4.2L | L6 | N/A | Coolant Temp Sensor |
| 2004 | GMC | Envoy | — | — | N/A | Coolant Temp Sensor |
| 2004 | GMC | Envoy XL | 4.2L | L6 | N/A | Coolant Temp Sensor |
| 2004 | GMC | Envoy XUV | 4.2L | L6 | N/A | Coolant Temp Sensor |
| 2004 | Isuzu | Ascender | 4.2L | L6 | N/A | Coolant Temp Sensor |
| 2004 | Oldsmobile | Bravada | — | — | N/A | Coolant Temp Sensor |
| 2003 | Chevrolet | Trailblazer | — | — | N/A | Coolant Temp Sensor |
| 2003 | Chevrolet | Trailblazer EXT | 4.2L | L6 | N/A | Coolant Temp Sensor |
| 2003 | GMC | Envoy | — | — | N/A | Coolant Temp Sensor |
| 2003 | GMC | Envoy XL | 4.2L | L6 | N/A | Coolant Temp Sensor |
| 2003 | Isuzu | Ascender | 4.2L | L6 | N/A | Coolant Temp Sensor |
| 2003 | Oldsmobile | Bravada | — | — | N/A | Coolant Temp Sensor |
| 2002 | Chevrolet | Trailblazer | — | — | N/A | Coolant Temp Sensor |
| 2002 | Chevrolet | Trailblazer EXT | — | — | N/A | Coolant Temp Sensor |
| 2002 | GMC | Envoy | — | — | N/A | Coolant Temp Sensor |
| 2002 | GMC | Envoy XL | — | — | N/A | Coolant Temp Sensor |
| 2002 | Oldsmobile | Bravada | — | — | N/A | Coolant Temp Sensor |
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