Skip the auto shop - Our mechanics make house calls

Q: Fluctuating coolant readings

asked by on

I have been getting a fluctuating reading on my coolant recently. My dashboard sensors are going from normal to 260 and back down. It goes up and down in readings the entire time I am driving. I changed the coolant, temperature sensors and thermometer. I didn't use a torque wrench to do this with. The problem still persists. Do you know what is going on? My engine seems to be a normal temperature.

Hello. Your fluctuating coolant temperature may be caused by a cracked cylinder head or leaking head gasket. It sounds like you have replaced everything else that could be causing this issue. If the head is cracked or the head gasket is leaking, this can cause combustion chamber gases to get into the cooling system. When this happens, it forms an air pocket. When an air pocket reaches the coolant temperature sensor, it will read hot because the air from the combustion chamber is very hot. I recommend having a local expert inspect your cooling system to determine if there are any emerging issues such as overheating or leaks that need to be addressed.

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

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: How do I display the trip A/B feature?

Your truck has a Base Message Center that keeps track of your vehicle's system functions. You can use this message center to display your vehicle's information and features. The Trip A/B feature logs the distance traveled for different trips. To...

Q: I have replaced radiator watepump ect still running hot

If you did not replace the thermostat then you should replace it and then refill the system after bleeding out all the air in the system. Check to make sure the fans come on when the temperature goes up. If...

Q: Is It Worth It to Buy My Own Scanner or Code Reader?

A code scanner is used to access the onboard diagnostic system (OBD) of your vehicle. Not all code scanners are created equal; there are many different scanner types. The most inexpensive scanners on the market today hookup to the OBD...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...