Symptoms of a Bad or Failing Coolant Level Sensor

The coolant level sensor is the electronic sensor that is responsible for measuring the coolant level of your engine. It is usually installed in the coolant reservoir or radiator, and measures the amount of coolant in the system to make sure that it is always at the proper level. When the level drops below a safe level the low coolant light will come on to alert the driver that coolant must be added. Low coolant is dangerous to the engine as the coolant is what keeps the engine from overheating during normal operation, so it is imperative to replace the coolant level sensor if it is failing.

1. Coolant Light stays on

One of the most common symptoms of a faulty coolant level sensor is a Coolant Level Light that stays on. If the sensor shorts, it can cause the Coolant Level Light to stay on. This is a problem because a permanently illuminated coolant light will not be able to properly alert the driver if the coolant level does drop low.

2. Low coolant

Another symptom of a problem with the coolant level sensor is low coolant. If the coolant level drops low and the light does not come on then that means the sensor or wiring are having a problem. The sensor is designed specifically to detect low coolant, so if the level in the reservoir drops low, and the light does not come on, that may be an indication of a problem with the sensor or perhaps the wiring.

3. Engine overheating

The engine overheating is another indicator of a problem with the sensor. Engine overheating can be caused by a variety of issues, usually not related to any sensors. However, if the overheating is related to coolant level, this may be an indicator of a problem with the sensor. If the coolant level drops low enough to cause overheating, and the low coolant light is not illuminated beforehand, then that may be an indicator of a problem with the sensor.

While the coolant level sensor doesn’t play a big role in engine performance or drivability, it does serve a very specific purpose in protecting the engine from dropping low in coolant and potentially overheating. For this reason, if you suspect that your coolant level sensor may be having an issue, have the vehicle diagnosed by a professional technician, such as one from YourMechanic. They will be able to inspect your vehicle and determine if your car will need a replacement coolant level sensor.


Next Step

Schedule Vehicle Engine Cooling Inspection

The most popular service booked by readers of this article is Vehicle Engine Cooling Inspection. Once the problem has been diagnosed, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. YourMechanic’s technicians bring the dealership to you by performing this job at your home or office 7-days a week between 7AM-9PM. We currently cover over 2,000 cities and have 100k+ 5-star reviews... LEARN MORE

SEE PRICING & SCHEDULING

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Recent Vehicle Engine Cooling Inspection reviews

Excellent Rating

(171,627)

Rating Summary
161,099
5,644
1,174
834
2,876
161,099
5,644
1,174
834
2,876

Dan

39 years of experience
975 reviews
Dan
39 years of experience
Hyundai Sonata V6-3.3L - Starter - Suwanee, Georgia
This is the fourth time Dan has worked on my car. As always, he is an expert and a true professional. I give him the highest possible rating and recommendation. You will not be disappointed. I will use Dan anytime I need work done on my car!
Honda Pilot - Power Steering Pump - Duluth, Georgia
Thanks again Dan!!!!! Awesome mechanic!!!!!

Patrick

33 years of experience
1408 reviews
Patrick
33 years of experience
Ford F-150 V8-5.4L - Shock Absorber Replacement (Front) - San Marcos, Texas
very good
Nissan 350Z - Rear Windshield Wiper Blade - Austin, Texas
Always early, quick work, and reasonable pricing. I've started telling my friends about yourmechanic

William

34 years of experience
517 reviews
William
34 years of experience
Mazda 3 L4-2.0L - Vehicle Engine Cooling Inspection - Phoenix, Arizona
Earlier than expected! Diagnosed car within an hour and had an estimate for repairs quick

Glenn

21 years of experience
38 reviews
Glenn
21 years of experience
Pontiac Grand Prix V6-3.8L Turbo - Vehicle Engine Cooling Inspection - Indianapolis, Indiana
Ok

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

Related articles

How to Replace an Intake Air Temperature Sensor
An air temperature sensor, or air charge temperature sensor, signals a car’s computer about the air-to-fuel ratio. Replacing one requires few tools.
How to Replace an Anti-Lock Brake Fluid Level Sensor on Most Modern Cars
The anti-lock brake (ABS) system has a fluid level sensor that fails when the warning light comes on or if there is low fluid in the reservoir.
Why Cooling System Repairs on a European Car Can Be Tricky
Repairing a cooling system, such as if there is a leak, can pose different obstacles. Many repairs may involve finding the radiator of the system.

Related questions

The fuel gauge moves up and down I never know how much gas I have
The fuel sending unit is in the fuel tank mounted to the fuel pump assembly. The sending unit is shorted or open and needs to be tested using a gauge tester or by removing it and measuring the resistance of...
Location of crankshaft position sensor with pictures
Hi there. The crankshaft position sensor is located at the rear of the engine block near the transmission. Unfortunately I cannot send over any pictures. If you need to have your crank sensor replaced, consider YourMechanic, as a certified mechanic...
is it possible to put crankshaft sensor where canshaft sensir goes, and visa versa?
For the question as to whether or not you can put the camshaft and crankshaft sensors into the wrong orifice, I don't see this being possible. The physical dimensions would be close, but the protrusion of the sensor pickup should...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com