Skip the auto shop - Our mechanics make house calls

Q: My car keeps running hot then it cools down

asked by on

My temperature gauge on my car will run cold, then hot, then cold again.

My car has 181523 miles.
My car has an automatic transmission.

A: Hi, thanks for writing in. There are two po...

Hi, thanks for writing in. There are two possibilities here: either the physical temperature of the engine is indeed fluctuating significantly, or the sensor and/or circuit that feeds the temperature gauge is malfunctioning. The sensor (and circuit) can be tested and, if necessary, a temperature data logger can be deployed to measure the engine temperature over time to see if the temperature is in fact fluctuating. If it is there could be an issue with the cooling system thermostat, water pump drive belt, radiator blockage and/or a malfunctioning cooling fan. YourMechanic would be pleased to evaluate the issue for you and identify the cause of the problem, that is whether it is electrical or something else.

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・Save up to 30%

Get a quote

What others are asking

Q: Key will not turn to start the car

Hello. This can be as simple as a dead battery. If the battery is low enough, then this will occur. I typically start by load testing the battery to see if that is the problem. If the battery is fine...

Q: Car only start when cold but dies once warm and wont start till complete cold

You may have more than one issue going on here for your 1987 Toyota Celica. The cold starting issue could possibly be caused by a failing fuel pump or even a temperature sensor. Heat increases resistance in electrical circuits, and...

Q: I DROVE THRU A FLOOD & MY CAR STALLED. NOW THAT IT STARTS ITS KNOCKING... WHAT CAN BE CAUSING THIS?

If you drove through deep water, chances are your engine took in some water and did internal damage to it. When engine suck in water, they cannot compress the water that gets into the cylinder, so it usually locks up...

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.