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Engine Coolant Temperature Sensor Guide for the 2019-2024 Buick Enclave

Learn to spot the signs of a failing coolant sensor and select the best new aftermarket replacement for your Enclave.

4 minutes to read 2019-2024 Buick Enclave
Difficulty
2/5
Est. Time
0.5 hrs
DIY Doable?
✅ Yes
Shop Labor
$95-$150
⚠️ Drivable, but... — You can drive, but it's not recommended for long distances as it can lead to poor fuel economy, overheating, or catalytic converter damage.
Key Takeaways
  • A bad ECT sensor on your Enclave can cause a check engine light, poor fuel economy, overheating, and rough running.
  • The most common related trouble code, P0128, is often caused by a stuck thermostat, not the sensor itself.
  • Replacement is a DIY-friendly task, located at the front of the engine and requiring a 19mm deep socket.
  • Premium aftermarket brands like Delphi and NTK offer OEM-level quality, while ACDelco is the original part.
The Engine Coolant Temperature (ECT) sensor is a critical component in your Buick Enclave's 3.6L V6 engine. It measures the temperature of the engine coolant and sends this information to the main computer, the Engine Control Module (ECM). The ECM uses this data to make vital adjustments to the air-fuel mixture, ignition timing, and when to turn the cooling fans on or off. A correct signal from this sensor ensures your engine runs efficiently, avoids overheating, and maintains optimal performance.

Is Your Enclave's Coolant Sensor Failing?

A bad Engine Coolant Temperature (ECT) sensor can cause a range of noticeable problems in your 2019-2024 Buick Enclave. Because the engine's computer relies on this sensor for critical information, a false signal can lead to poor performance and potential engine stress. One of the first things you might notice is the check engine light on your dashboard. Other common signs include the engine running rough, especially at idle, or a sudden drop in fuel economy because the computer incorrectly adjusts the fuel mixture. In some cases, you might see the "Engine Hot A/C Off" message on your display, or the cooling fans might run constantly at high speed, even when the engine is cold. This is a fail-safe measure the vehicle takes when it can't get a reliable temperature reading.

Known Issues and Bulletins

While no specific recalls exist for the ECT sensor on the 2019-2024 Buick Enclave, a Technical Service Bulletin (TSB) #18-NA-023 was issued for 2018 models that may also be relevant to early production 2019 models. This TSB addresses a condition where the check engine light may illuminate and set a code P111E (Engine Coolant Temperature Sensor Not Plausible). The fix involves a software update to the Engine Control Module (ECM) and checking the sensor's connector for a secure fit. If you experience these specific symptoms, a dealership may need to perform this software update.

Choosing the Right Aftermarket Sensor

When replacing the ECT sensor, you have several aftermarket options that offer a balance of quality and value. Not all brands are created equal, but for a part like this, a high-quality aftermarket sensor can perform just as well as the original part.

  • Premium Aftermarket (OEM-Grade): Brands like ACDelco (the original GM parts supplier) and Delphi are top-tier choices. They are engineered to meet or exceed original specifications. NGK (NTK) is another excellent brand known for its sensor technology and rigorous testing, often matching OE form and function precisely.
  • Quality Aftermarket: Brands such as Standard Motor Products (Standard Ignition), Hella, and Walker Products have a solid reputation for producing reliable engine management components that offer good performance and durability.
  • Value-Oriented: Brands like Holstein, Global Parts, and Motorad provide a more budget-friendly option. They can be a good choice for drivers looking for a cost-effective repair, though consistency may vary compared to premium brands.

Pro Tip: The most common cause for the P0128 trouble code ("Coolant Temperature Below Thermostat Regulating Temperature") is a thermostat that is stuck open, not a faulty sensor. If you have this specific code, it's wise to inspect the thermostat first before replacing the ECT sensor.

🎬 Watch: Understanding the P0128 code and how to fix it.

Cost of Replacing the Engine Coolant Temperature Sensor

The cost to replace the ECT sensor can vary. The part itself is inexpensive, but labor costs can differ depending on your location and shop rates. Some estimates show a wide range, so it's best to get a specific quote.

Part Type Estimated Cost
New Aftermarket Part $10.62 - $50.56
New OEM Part (ACDelco) $25 - $60
Shop Labor $95 - $257
Total Professional Replacement $105 - $317

Frequently Asked Questions

Where is the ECT sensor on a 2019-2024 Buick Enclave?

The Engine Coolant Temperature sensor on the 3.6L V6 engine is located on the front of the engine, near the thermostat housing and above the exhaust manifold. 🎬 See this shortcut for reaching the sensor on the 3.6L engine. It is positioned near the oil dipstick tube and may be covered by a small heat shield.

Can I replace the Buick Enclave's ECT sensor myself?

Yes, this is a feasible DIY job for someone with basic mechanical skills. It requires a 19mm deep socket to remove the sensor. The main challenges are reaching the sensor in a tight space and working quickly to minimize coolant loss. 🎬 Watch this walkthrough of the sensor replacement process. Always perform this repair on a cold engine to avoid burns and release any pressure from the cooling system by opening the coolant cap first.

What happens if I don't replace a bad coolant sensor?

Ignoring a faulty ECT sensor can lead to several issues. Your vehicle may run on a rich fuel mixture, which wastes gas and can eventually damage the catalytic converter. It can also cause the engine to overheat if the cooling fans don't turn on, potentially leading to severe engine damage.

Is an ACDelco sensor better than other aftermarket brands?

ACDelco is the original equipment manufacturer for GM vehicles, so it guarantees a perfect fit and function. However, premium aftermarket brands like Delphi and NTK are also OEM suppliers for many automakers and produce sensors of equal or better quality. For a simple part like an ECT sensor, a reputable aftermarket brand often provides the best value without sacrificing reliability.

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Technical Specifications

OEM Part Numbers: 12639899

Connector Shape: Round, Terminal Pins: 2, Thread Size: M12x1.5

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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.

Year Coverage
This article covers the Engine Coolant Temperature Sensor for:
  • Buick Enclave: 201920202021202220232024
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