Skip the auto shop - Our mechanics make house calls

Q: My car starts to run hot if I cannot maintain a consistent speed where air is moving across the engine.

asked by on

My car has started to run hot when I cannot maintain a consistent speed where air is moving across the engine. This is especially true in the current hot weather. If I am on the highway and moving I am fine, the temp stays in the normal range but if I get into a situation where I am stopped in traffic or at a red light and no air is moving across the engine, the temperature gauge starts to creep up towards hot. If I turn my A/C off, that helps right away or if I start going again and get air movement the temp comes back down. What is causing this? Is my thermostat going bad? How much does that cost to fix?

My car has 185700 miles.
My car has an automatic transmission.

A: Hey there, your car has an electric cooling...

Hey there, your car has an electric cooling fan. It should start automatically when the engine gets to a certain temperature or when you switch the A/C is on. In hot weather with the A/C on, the fan should switch to a higher speed. If the fan is not coming on, or is switching to high speed with the A/C on, that would cause a run hot condition.

Here is a simple check: open the hood and start the car with the A/C off. Depending on the temperature, the electric fan on the radiator should not be running. Switch the A/C on. The fan should come on within 30 seconds if it is hot outside. If it does not, then it could be a bad fan relay or temperature sending switch. The cost of repair will depend on the part that is faulty. If you need help having this checked, a certified professional from YourMechanic can inspect the slight overheating issue and make adjustments to prevent further issues.

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: Changed timing chain guide and tensioner. Now car starts good sounds good until warm them starts to make loud knocking. 2004 Nissan Maxima

I am working on this

Q: My car wont start/crank

Hello and thank you for contacting YourMechanic. What happened is that the power cables that are directly from the battery went to ground causing a mass surge through the vehicle's fuse box. This causes the engine's computer to think that...

Q: Why does my temp gauge read high before car is even started been sittin for bout 3 weeks without a battery

On some vehicles, the instrument cluster may do a sweep on start-up as a way for the computer to check operation. If the temperature gauge goes to the high mark and stays there, you may have a malfunctioning engine coolant...

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...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
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.