Skip the auto shop - Our mechanics make house calls

Q: Engine temperature shows overheating

asked by on

Driving on hwy temp gauge reading hot engine safe mode kicks in. Replaced water pump and thermostat no blockage in radiator. Temperature gauge reads hot. Heater will not blow hot air. Could it be coolant temp sensor?
My car has an automatic transmission.

Hey there. If the heater valve (for the passenger compartment heater core) is working and you do have the heat set to high but there is no heat, there is either trapped air in the cooling system or a physical blockage (which includes the possibility of collapsed hose(s)). Either of those problems would cause engine overheating.

There are air purge points on high points in the cooling system which if you open during refilling with coolant, will help to lessen the possibility of trapped air but even opening the purge points is not foolproof. On occasion, I have only been able to "dislodge" trapped air by swerving while driving and this literally forcing the air to move out and get "trapped" elsewhere at the top of radiator where it will not block flow. Yes, a defective cooling sensor can cause overheating by either failing to actuate cooling fans and/or creating a lean running condition, misfires, and so forth. But that sensor is fairly easy to evaluate with a volt ohmmeter and thus rule in or out (of course just because the sensor works, that doesn’t mean the PCM is getting the signal, so the circuit integrity has to be confirmed as well). If you would like to have this looked at by a pro, a certified technician from YourMechanic can come to your car’s location to diagnose the overheating issue and follow through with repairs.

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: Temperature gauge sits on cold always

This is a common issue on this generation of the Chevy Malibu. This could be any one of a few problems. This could be a result of a bad BCM (Body Control Module). This is a module in your car...

Q: What causes my truck to die when I take my foot off the gas pedal while in a turn?

Hi and thanks for contacting Your Mechanic. What seems to be happening is the idle air control valve (IAC) is not working. This valve controls the idle of the engine when the gas pedal and the throttle position sensor is...

Q: I think my suspension is going out in my car. Does my car use shocks, struts, or both?

Hello. Your car uses struts on all four corners of your vehicle. These work the same way as shocks, they simply mount different and perform a little better. The cost will very depending on the brand of the struts that...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
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...
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...