Can A Bad Coolant Temp Sensor Cause Rough Idle

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There are many things that can cause a rough idle, but one potential cause is a bad coolant temp sensor. If the sensor is not providing accurate information to the engine computer, it can cause the engine to run erratically. So, if you have a coolant temp sensor that is starting to fail, it could potentially cause a rough idle. You should have the sensor checked and replaced if necessary to see if that solves the problem.

In this article, we’ll discuss the symptoms, how to identify a failing coolant temp sensor and how it can lead to a rough idle.

Can a Bad Coolant Temp Sensor Cause Rough Idle?

ACDelco Professional 213-4514 Engine Coolant Temperature Sensor

A bad coolant temp sensor can cause a number of problems with your car, including a rough idle. The sensor is responsible for measuring the temperature of the coolant and relaying that information to the engine control unit. If the sensor is not working properly, it can cause the engine to run rough or even stall. 

In most cases, it will make the check engine light to come on. If you suspect that your coolant temp sensor may be going bad, it’s important to have it checked out by a mechanic as soon as possible.

Can a Faulty Coolant Temperature Sensor Cause High Idle Speed?

ACDelco Professional 213-4514 Engine Coolant Temperature Sensor

As the coolant temperature sensor is responsible for detecting the temperature of the engine coolant, if it’s not working properly, it can cause the engine to idle higher than normal. In some cases, a faulty coolant temp sensor can also cause the engine to overheat. 

Can a Faulty Coolant Temperature Sensor Cause Erratic Idling in This Regard?

ACDelco Professional 213-4514 Engine Coolant Temperature Sensor

Indeed, the coolant temperature sensor is responsible for detecting the temperature of the engine coolant. If it’s not working properly, the engine may idle erratically as it tries to compensate for the wrong information it’s receiving from the sensor. 

6 Symptoms of a Bad Coolant Temp Sensor

The following are some easy ways to check and see if your coolant temp sensor may be going bad:

Check Engine Light

The first thing you may notice is the check engine light turning on in your car. This usually means that there is a problem with the vehicle and it might even point towards a faulty sensor although it could be something else entirely. If the check engine light is on, it’s worth taking your car to a mechanic to get it checked out and see if the sensor is the issue.

Also Read: Check Engine Light Flashing When Accelerating

Irregular Temperature Readings

For example, if the temperature gauge on your dash is reading higher than it should be, or if it’s fluctuating erratically, this could be a sign that the coolant temp sensor is going bad. You can if this is true also by simply touching the coolant hose. If it feels hotter or cooler than it should be, and yet the gauge is reading differently, this is could be a sign that the sensor needs to be replaced.

Also Read: Why is my Temperature Gauge not Going Up?

Black Smoke From the Exhaust

When the engine is running, black smoke coming from the exhaust could be a sign that the coolant temp sensor needs to be replaced. This is because the sensor tells the computer how hot the engine is running and if it’s not working properly, the computer may be injecting too much fuel into the engine which can cause it to run lean and produce black smoke as the fuel is not being burned properly.

Also Read: Why Does My Car Smell Like Burnt Rubber?

Engine Overheating

When the sensor is not functioning properly, it can cause the engine to overheat. This is because the sensor helps regulate the coolant flow and if it’s not working, the engine may not be getting enough coolant or it may not be flowing properly. This leads to the engine overheating and can cause serious damage if not fixed.

Also Read: Car Overheating When Idle

Poor Fuel Economy

When the system is running lean, it can cause poor fuel economy. This is because the sensor communicates with the ECU and thus helps regulate the mixture of fuel and air going into the engine. If it’s not working properly, too much fuel may be injected into the engine or which can lead to poor fuel economy.

Rough Idling

Last but not least, a bad coolant temp sensor can also cause rough idling. This is because the sensor helps regulate the engine’s idle speed and if it’s not working properly, the engine may idle erratically or at a higher speed than normal. This can be annoying and may even cause the engine to stall.

Also Read: How to tell if your Coolant Temp Sensor is Bad

FAQs

Can a High Idle Speed Cause Damage?

High idle speeds can cause engine damage from overheating and excessive wear. Components such as spark plugs, cylinders, and exhaust systems end up damaged the most from the fuel not being burnt properly in its ideal conditions.

Can a Bad Coolant Temperature Sensor Cause Car Not to Start?

A bad coolant temperature sensor can cause your car not to start. The engine needs the correct information about the temperature of the coolant in order to properly start and run. If the sensor is faulty, it will give the engine computer false information which can cause starting and running issues.

Can a Bad Coolant Temperature Sensor Cause Misfire?

The answer is yes. A bad coolant temperature sensor can cause your engine to misfire. The engine needs the correct information about the temperature of the coolant in order to run properly. If the sensor is faulty, it will give the engine computer false information which can cause misfires as the engine will not optimal adjustments for running at the correct temperature.

How Much Does It Cost to Replace a Coolant Temperature Sensor?

Replacing a coolant temperature sensor is a relatively inexpensive repair. The cost of the sensor itself is usually around $30-$50 depending on the make and model, and the labor to install it is typically less than an hour.

Conclusion 

In summary, a bad coolant temp sensor can cause a number of problems such as black smoke from the exhaust, engine overheating, poor fuel economy, and rough idling. If you notice any of these issues with your vehicle, it’s important to have it checked out by a mechanic to diagnose the problem and determine if the coolant temp sensor is the culprit.

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