Symptoms of a Bad or Failing Coolant Temperature Switch (Sensor)

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Cost of Replacing a Bad or Failing Coolant Temperature Switch (Sensor)

Common signs include poor fuel economy, black smoke coming from the engine, engine overheating, and the Check Engine Light turning on. Our certified technicians can come to you and diagnose the problem. You will receive a $30 credit towards any follow-up repairs that result from the diagnostic. Following are example prices for Coolant Temperature Switch (Sensor) Replacement. Click on the button below to get an upfront quote for your car.

Cars Estimate Parts Cost Labor Cost Savings Average Dealer Price
2005 Saturn Vue $121 $50.76 $70.00 23% $158.26
2004 Ford E-250 $82 $11.68 $70.00 31% $119.18
2008 Chrysler Sebring $100 $30.40 $70.00 27% $137.90
2011 Acura TL $128 $58.48 $70.00 22% $165.98
2006 Mercedes-Benz SL600 $96 $25.98 $70.00 28% $133.48
2014 Audi S6 $179 $81.12 $98.00 22% $231.62
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How to Diagnose a Bad or Failing Coolant Temperature Switch (Sensor)?

Coolant Temperature switch

The coolant temperature sensor, also known as the coolant temperature switch, is an engine management system sensor that is used to monitor the temperature of the engine’s coolant. Most coolant temperature sensors operate using electrical resistance to measure the temperature of the coolant. This signal is then sent to the computer so that changes can be made to the engine’s timing and fuel calculations for optimal performance, as engines require more fuel when they are cold, and less fuel when they are fully warmed up. The computer will also scale back engine performance settings if it detects that the engine temperature is too high, in order to protect the engine from possible damage due to overheating.

Because temperature plays such a vital role in engine performance calculations, any problem with the coolant temperature sensor can quickly translate into an engine performance issues. Usually a problem with the coolant temperature sensor will cause a few symptoms that alert the driver of a potential problem that should be thoroughly inspected.

1. Poor fuel economy

One of the first symptoms associated with a problem with the coolant temperature sensor is poor fuel economy. If the coolant temperature sensor goes bad it can send a false signal to the computer and throw off the fuel and timing calculations. It is not uncommon for the coolant temperature sensor to fail and send a permanently cold signal to the computer. This will cause the computer to think the engine is cold, even when it is not, and as a result will use more fuel than necessary. This will reduce fuel economy, and may hinder engine performance.

2. Black smoke from engine

Another symptom of a possible problem with the coolant temperature sensor is black smoke from the vehicle’s exhaust. If the coolant temperature sensor fails and sends a cold signal to the computer, this can confuse the computer and cause it to unnecessarily enrich the fuel mixture. If the fuel mixture becomes excessively rich to the point where the fuel cannot be adequately burned in the combustion chamber, it will burn up in the exhaust pipes and cause black smoke. In severe cases, the black smoke may be considerable enough to warrant not driving the vehicle.

3. Overheating engine

Another symptom of a problem with the coolant temperature sensor is an overheating engine. The coolant temperature sensor can also fail in a manner that causes it to send a permanently hot signal. This can cause the computer to incorrectly compensate for a lean signal, which can result in overheating, and even misfires or engine ping.

4. Check Engine Light comes on

An illuminated Check Engine Light is another symptom of a potential problem with the coolant temperature sensor. For some vehicles the computer will set off a Check Engine Light if it detects a problem with the sensor’s signal or circuit. The Check Engine Light will remain on until the issue is addressed.

The coolant temperature sensor is one of the most important engine management sensors, as its reading plays a key role in calculations which affect engine performance. For this reason, if you suspect that your coolant temperature sensor is having an issue, have the vehicle inspected by a professional technician from YourMechanic. They will be able to diagnose your vehicle and determine if you need a coolant temperature switch replacement.

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Recent Coolant Temperature Switch (Sensor) Replacement reviews

Excellent Rating


YourMechanic Coolant Temperature Switch (Sensor) Replacement Service

Average Rating

4.7/5

Number of Reviews

123

Rating Summary
108
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2
7
108
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2
7

Tyrone

8 years of experience
398 reviews
Tyrone
8 years of experience
Excellent job. Very nice guy to talk to, found the problem that other places (including Cadillac dealership) could not.
2004 CADILLAC ESCALADE - COOLANT TEMPERATURE SWITCH (SENSOR) - SPRINGFIELD, VIRGINIA

Richard

10 years of experience
415 reviews
Richard
10 years of experience
Richard did an awesome job. Showed up promptly and handled each of the repairs accordingly. I got to hang out inside my home and work while he was working on the car outside.
2012 DODGE CHALLENGER - COOLANT TEMPERATURE SWITCH (SENSOR) - LAS VEGAS, NEVADA

Keith

23 years of experience
113 reviews
Keith
23 years of experience
Keith arrived on time, was super professional and friendly, fixed my car and that was that. I couldn't ask for a better experience.
2011 CHEVROLET TAHOE - COOLANT TEMPERATURE SWITCH (SENSOR) - FORT WORTH, TEXAS

Cesar

6 years of experience
162 reviews
Cesar
6 years of experience
Cesar's is very patient and helpful. He took care of my Saab for me. Great mechanic, I would recommend him to my family and friends.
2005 SAAB 9-3 - COOLANT TEMPERATURE SWITCH (SENSOR) - LYNNWOOD, WASHINGTON

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