2009-2010 Hummer H3T Engine Coolant Temperature Sensor Guide
Keep your Hummer H3T's engine running right by understanding and replacing a faulty coolant temperature sensor.
- A faulty ECT sensor can cause a Check Engine Light, poor fuel economy, and incorrect temperature gauge readings.
- The code P0128 is common but can be caused by either the thermostat or the ECT sensor; it's often wise to inspect both.
- For best results, choose a top-tier aftermarket brand like ACDelco or Delphi for this critical sensor.
- Replacement is a feasible DIY job for those with some experience, but accessing the sensor on the H3T engine can be challenging.
Is your Hummer H3T acting up? It could be the coolant temp sensor.
If your 2009-2010 Hummer H3T is showing a check engine light, getting poor gas mileage, or has a temperature gauge that's acting strange, a faulty Engine Coolant Temperature (ECT) sensor could be the culprit. This sensor tells the truck's computer how hot the engine is, which affects everything from fuel mixture to the cooling fans. When it fails, it can cause a range of problems, some of which can seem unrelated.
🎬 Learn more about common symptoms and how to test your sensor.Watch for Code P0128
A very common trouble code for the Hummer H3T is P0128 - Coolant Temperature Below Thermostat Regulating Temperature. While this code often points to a thermostat that is stuck open, it can also be triggered by a faulty ECT sensor giving an incorrect reading. It's common to replace the thermostat first, but if the problem persists, the sensor is the next logical step.
Choosing the Right Aftermarket Sensor
When replacing the ECT sensor on your H3T, you have several good aftermarket options. You don't necessarily need to go to a dealer for this part.
- Top-Tier Aftermarket (OEM-Equivalent): Brands like ACDelco and Delphi are excellent choices. ACDelco is the original GM parts supplier, so their Professional (Gold) line is a direct equivalent to the factory part. Delphi is also a major OEM supplier known for high-quality sensors that meet or exceed factory specifications. These are your best bet for reliability and a perfect fit.
- Reputable Aftermarket: Brands such as NGK, Standard Ignition (SMP), and Hella offer quality replacement parts that are a good balance of price and performance. They are well-known in the industry and produce reliable components.
- Standard/Economy Tier: Other brands like Four Seasons, Walker Products, and various store brands will get the job done and are budget-friendly. While they may not have the same long-standing reputation as the top-tier brands for electronics, they are a viable option for a simple sensor replacement.
Pro Tip: For a critical electronic sensor like the ECT, spending a few extra dollars on a top-tier brand like ACDelco or Delphi can provide peace of mind and help you avoid having to do the job twice.
Cost of Replacing the Hummer H3T Coolant Temperature Sensor
The cost for this repair is low if you do it yourself, as the part itself is inexpensive. Shop labor costs can vary significantly.
| Item | Estimated Cost |
|---|---|
| New Aftermarket Sensor | $16.81 - $43.11 |
| Estimated Shop Labor | $95 - $251 |
| Total Professional Replacement | $110 - $295+ |
Note: Prices are estimates and can vary based on location, specific brand, and shop labor rates. Some repair estimates may bundle this with other services, leading to higher quoted prices.
Frequently Asked Questions
Where is the ECT sensor located on the 2009-2010 Hummer H3T?
On the Hummer H3 and H3T, the ECT sensor is located on the driver's side of the cylinder head, below and toward the back. It can be difficult to access due to its position underneath other components. Some owners have noted that the header heat shield can be very close to or even touching the sensor, making removal tricky.
Is this a difficult DIY job?
For an experienced DIY mechanic, it's manageable. The main challenge is access. You will need a special deep socket for the sensor. Some mechanics access it from the top after removing the alternator, while others go through the driver's side wheel well. 🎬 Watch this step-by-step guide on H3 sensor removal and installation. Be prepared for some coolant to spill when the old sensor is removed; have the new sensor ready to install quickly to minimize loss.
Are there any recalls for the ECT sensor on the H3T?
No, there are no specific recalls for the engine coolant temperature sensor. The 2009-2010 H3T did have recalls for an HVAC blower motor connector that could overheat and for a hood louver that could detach, but neither is related to the ECT sensor.
Should I replace the thermostat at the same time?
It's a good idea, especially if your truck is throwing a P0128 code. A failing thermostat is a common issue on the H3T. Since you are already working on the cooling system, replacing both the thermostat and the sensor 🎬 See how to replace the thermostat and sensor on your Hummer. can save you from a future repair and ensure the cooling system is operating correctly.
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Technical Specifications
OEM Part Numbers: 19236568 12601050
The sensor is typically made of brass and has a 2-pin connector. Common thread sizes are M12 x 1.5 or 3/8" - 18 NPTF, so verifying the correct part for your specific engine (3.7L I5 or 5.3L V8) is crucial.
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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.
- Hummer H3T: