Skip the auto shop - Our mechanics make house calls

Q: Could it be the coolant sensor?

asked by on

My car keeps over heating. I replaced everything. Finally figured out that what ever tells my electric thermostat to open is not doing it's job. My heat had does not show that my car is running hot but it is. So we took the thermostat out and the car does not run hot is this my coolant sensor?

My car has 136000 miles.
My car has an automatic transmission.

A: Hi and thank you for contacting YourMechani...

Hi and thank you for contacting YourMechanic. If your vehicle engine is overheating, there are 3 different things that can cause this problem.

The first is the thermostat is not opening up. A stuck thermostat will cause an engine to overheat.

The second thing is a radiator or reservoir cap that will not hold pressure will cause the coolant to boil and make the engine overheat.

The third thing that could cause an engine to overheat is a burned head gasket making hot exhaust gasses into the cooling system and not properly conducting a heat exchange.

I recommend replacing the thermostat and the sensor. This eliminates the thermostat and signal for the thermostat. If the engine is still overheating, then replace the radiator or reservoir cap. If the engine still overheats, then it is possible that the engine has a burned head gasket.

You could get a block heater and place it over the radiator cap with the cap off and the engine running. When steam comes up, squeeze the plunger and allow the air to come in contact with the blue fluid inside the block tester. If the blue fluid changes color to orange or yellow, then the head gasket is burned. If the fluid does not change color, then it is possible that the water pump has failed.

To avoid any unnecessary repairs, I recommend having a certified professional, such as one from YourMechanic, diagnose the cooling system of your engine.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Car overheating due to radiator crack

When your engine is idling, the vehicle is likely stopped which lowers the airflow through the radiator. The more airflow the radiator receives the more likely the engine is to remain cool. When the air conditioning is turned on the...

Q: My car is running hot

This engine #3 cylinder is the third cylinder from the front of the motor near accessory belt which is cylinder number 1. This engine does not have an air bleed for the coolant system and may require 3 to 4...

Q: Temperature guage stays on cool, heat inside is not very warm

If your heater is not getting warm enough and the engine is not reaching operating temperature for a long time then your engine most likely has a thermostat that is stuck open. A stuck open thermostat can be verified by...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.