1987-1991 Pontiac Tempest Coolant Temperature Sensor: A Complete Guide
Learn the common problems, symptoms, and replacement tips for your Tempest's coolant sensor.
- A bad coolant sensor is a common cause of poor fuel economy, black exhaust smoke, and potential overheating on the 1987-1991 Tempest.
- For this vehicle, a standard aftermarket sensor is a reliable and cost-effective solution.
- Replacement is a simple, DIY-friendly job that can be done in under 30 minutes with basic tools.
- There are no recalls for this part; failures are due to normal aging.
Is Your Pontiac Tempest Coolant Temp Sensor Failing?
A bad Engine Coolant Temperature (ECT) sensor can cause a variety of issues that might seem unrelated. Because the sensor tells the computer how much fuel to inject, a bad sensor can trick the computer into thinking the engine is cold when it's actually warm. This results in a rich fuel mixture, leading to several noticeable symptoms.
Common Symptoms of a Bad ECT Sensor
- Poor Fuel Economy: The engine gets too much gas, wasting fuel.
- Black Smoke from Exhaust: This is a clear sign of unburned fuel from a rich mixture.
- Check Engine Light: Your Tempest's computer will trigger a light and store a fault code, often Code 14 or 15 for this model year.
- Engine Overheating: If the sensor doesn't tell the computer the engine is hot, the electric cooling fans may not turn on when needed.
- Hard Starting: The engine may be difficult to start, especially when it's already warm.
- Erratic Temperature Gauge: The gauge on your dashboard may give strange or incorrect readings.
Choosing the Right Aftermarket Sensor
For a vehicle like the 1987-1991 Pontiac Tempest, which shares many parts with the Chevrolet Corsica, finding parts is straightforward. The technology for this sensor is simple and well-established. A standard aftermarket replacement part offers excellent value and reliability for this application. There is no significant benefit to searching for a rare and expensive New Old Stock (NOS) OEM part. The "Replacement" brand sensor is a standard, reliable choice designed to meet original specifications and restore proper function to your engine management system.
Cost of Replacing a Coolant Temperature Sensor (1987-1991 Pontiac Tempest)
| Part Type | Estimated Cost | Notes |
|---|---|---|
| New Aftermarket | $18.79 | This is the most common and cost-effective option. |
| New OEM | $40 - $75 | May be difficult to find; offers no significant benefit for this vehicle. |
| Shop Labor | $50 - $100 | The job takes less than an hour, so labor costs should be minimal. |
Pro Tip: Before replacing the sensor, check the electrical connector and wiring. A corroded or loose connector can mimic the symptoms of a failed sensor and is a much simpler fix.
Frequently Asked Questions
Where is the coolant temperature sensor located on a 1987-1991 Pontiac Tempest?
The ECT sensor is usually screwed into a coolant passage on the engine, often near the thermostat housing where the large upper radiator hose connects. It will have a two-wire electrical connector.
Can I replace this sensor myself?
Yes, this is a very DIY-friendly repair. It typically takes less than 30 minutes with basic tools like a deep socket and ratchet. It's best to perform the replacement when the engine is completely cool to avoid burns and minimize coolant loss.
What happens if I don't replace a bad ECT sensor?
Ignoring a bad sensor will lead to continued poor fuel economy, potential damage to your catalytic converter from unburned fuel, and a risk of the engine overheating if the cooling fans fail to activate. It's a cheap and easy fix that prevents more expensive problems down the road.
Are there any recalls for the Pontiac Tempest coolant sensor?
No, there are no specific recalls or technical service bulletins (TSBs) from the NHTSA for the coolant temperature sensor on the 1987-1991 Pontiac Tempest. Any failures are due to the age and normal wear of the component.
Technical Specifications
OEM Part Numbers: 25036708 25036979 12146312 15326386
Typically a 2-pin, brass, threaded sensor with an oval connector.
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Pontiac Tempest: