Oldsmobile Cutlass 1987-1999 Engine Coolant Temperature Sensor Guide
A failing coolant sensor can cause poor fuel economy, overheating, and a check engine light on your Cutlass.
- A bad ECT sensor commonly causes a Check Engine Light, poor fuel economy, and overheating on a Cutlass.
- For best results, choose an OE-level brand like ACDelco or Delphi, as they were original suppliers to GM.
- Replacement is a simple DIY task for most owners, requiring basic tools and access near the thermostat housing.
- No recalls or TSBs are specifically associated with this part, but sensor failure is a known issue on these cars.
Is your Cutlass running rough or getting bad gas mileage?
A faulty Engine Coolant Temperature (ECT) sensor could be the culprit. This sensor tells your car's computer how hot the engine is, which affects everything from fuel injection to the cooling fans. When it fails, it can send incorrect signals, leading to a variety of performance problems. On these GM vehicles, ECT sensor failure was a relatively common issue.
Symptoms of a Failing ECT Sensor
If the ECT sensor on your Cutlass is going bad, you'll likely notice one or more of these signs:
- Check Engine Light: This is often the first sign. The computer detects a problem with the sensor's signal and stores a trouble code. Common codes include P0115, P0117, and P0118.
- Poor Fuel Economy: If the sensor wrongly tells the computer the engine is cold, the computer will enrich the fuel mixture, wasting gas.
- Black Smoke from Exhaust: A very rich fuel mixture may not burn completely, resulting in black smoke from the tailpipe.
- Engine Overheating: A bad sensor might fail to signal the cooling fans to turn on when needed, causing the engine to overheat.
- Rough Idle or Hard Starting: The wrong fuel and timing adjustments can make the engine run poorly, especially when idling or trying to start.
- Inaccurate Temperature Gauge: The gauge on your dashboard may read incorrectly, showing hot when the engine is cold or vice-versa.
No Recalls or TSBs Found
Our search of the National Highway Traffic Safety Administration (NHTSA) database and other sources found no specific recalls or Technical Service Bulletins (TSBs) for the engine coolant temperature sensor on 1987-1999 Oldsmobile Cutlass models.
Choosing the Right Aftermarket Sensor
For a critical sensor like the ECT, quality matters. While many aftermarket options exist, they can be grouped into tiers based on their reputation as original equipment (OE) suppliers.
Tier 1: OE-Level Quality
These brands are often the original suppliers to GM. Choosing one of these is the closest you can get to buying the part from an Oldsmobile dealer.
- ACDelco: As GM's own parts brand, ACDelco is the original equipment manufacturer and is engineered to the exact factory specifications for your Cutlass.
- Delphi: A major OE supplier for General Motors, Delphi parts are considered to be of equivalent quality and fit to the original.
Tier 2: Reputable Aftermarket
These brands have a strong reputation for producing reliable parts that meet or exceed OEM specifications.
- NGK / NTK: Well-known for ignition parts and sensors, NTK offers high-quality ECT sensors.
- Standard Ignition (SMP): A long-standing brand in the aftermarket, known for quality electronic components.
- Beck Arnley: Focuses on providing parts that match the original in form, fit, and function.
Tier 3: Standard Replacement
These brands offer a functional and affordable solution for repairs.
- Four Seasons
- Walker Products
- Hella
Pro Tip: Check the Connector
Over time, the plastic electrical connector for the ECT sensor can become brittle and break when you try to unplug it. Inspect the connector carefully. Some sensors are available as a kit with a new connector pigtail. ACDelco sometimes recommends a specific mating connector to be used with their sensor.
Cost of a New Engine Coolant Temperature Sensor
The cost for this repair is very reasonable, especially if you do it yourself. The part itself is inexpensive, and labor is minimal.
| Part Type | Price Range |
|---|---|
| New Aftermarket | $12.58 - $37.74 |
| Shop Labor | $50 - $120 |
Note: Prices are estimates and can vary based on brand, retailer, and your location. The shop labor estimate is for replacing the sensor only.
Frequently Asked Questions
Where is the ECT sensor on my Cutlass?
The location can vary depending on your engine. It is typically threaded into the engine block, cylinder head, or intake manifold near the thermostat housing. For example, on a 1995 Cutlass with the 3.1L V6 engine, the sensor is located near the thermostat housing. Always confirm the location for your specific year and engine before beginning work.
Can I drive with a bad ECT sensor?
It is not recommended for an extended period. A bad sensor can cause poor performance, terrible fuel economy, and potentially lead to the engine overheating without warning, which can cause severe engine damage.
What's the difference between the ECT sensor and the temperature sender?
They are often two separate parts on older vehicles. The Engine Coolant Temperature (ECT) sensor sends information to the car's computer. The coolant temperature sender (or switch) sends information to the temperature gauge on your dashboard. On some vehicles, one sensor may perform both functions. It's important to identify which one you need to replace.
How do I reset the Check Engine Light after replacement?
After replacing the sensor, the Check Engine Light may turn off on its own after several driving cycles. To clear it immediately, you can disconnect the negative battery terminal for about 10-15 minutes. Alternatively, you can use an OBD-II scanner to read and clear the trouble codes.
Technical Specifications
OEM Part Numbers: 213-928 213-4333
The sensor is a two-wire thermistor that threads into a coolant passage. The connector style and thread size may vary depending on the engine (e.g., 2.2L, 3.1L, 3.3L). Always verify the part for your specific engine.
We Have This Part in Stock
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.
- Oldsmobile Cutlass:
- 🛍️ Shop This Part
- Is your Cutlass running rough or getting bad gas mileage?
- Symptoms of a Failing ECT Sensor
- No Recalls or TSBs Found
- Choosing the Right Aftermarket Sensor
- Tier 1: OE-Level Quality
- Tier 2: Reputable Aftermarket
- Tier 3: Standard Replacement
- Pro Tip: Check the Connector
- Cost of a New Engine Coolant Temperature Sensor
- Frequently Asked Questions
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