Q: No A/C or heat and car is overheating

asked by on

At end of summer my AC started to blow warm n spurts- sometimes cold sometimes hot. If I turned the knob on dash from cold to hot back to cold it would start to blow cold again. When if started to get cooler at nite n past month I turned heat on & it was blowing cold so I played the knob game again to get heat but didn't work as well. Very random heat. I already new my egr valve plugged up & had an appt w my mechanic 2 fix that n a wk.during this wk it turned cold at night & n morn when I'd leave to go to work/school early the temp gauge would shoot up to red lined fairly qickly. Light would come on hang there mayb 10 seconds at most then gauge start to drop & light would go out & temp would straighten out. I fig was the thermostat going bad & staying closed then opening up & all going back to norm.called mechanic told him needed to add that to fix it list.. tried to open overflow (as there is no visible radiator on this car) & the cap won't come off- it's stripped.

My car has 308000 miles.
My car has an automatic transmission.

Hello. You may have two problems here. The engine temperature gauge behavior could be a thermostat going nuts as you describe. I would certainly check ground connections for the engine temperature sensor, and the engine-to-chassis connections in general. It may be a wiring issue.

It is possible you have a blown head gasket issue, but if so the temperature would not likely come back down very quickly at all. I would recommend having an overheating inspection completed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment and estimate for repairs. The erratic heater/AC behavior may be a malfunctioning HVAC control, or possibly a heater control valve that is sticking. Getting the engine temperature back to steady operation first will make the HVAC diagnosis much easier.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. No A/C or heat and car is overheating

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: Step by step troubleshooting of DTC fault codes

Each of these codes are for different components and since you swapped the motor with a different size motor than what the car had may be a big problem. You would need to have each code diagnosed separately to see...

Q: Noise when I turn the wheel and go over a bump.

Hi there. It sounds like there could be a fault with the strut mount, strut assembly, outer tie rod, ball joint, or control arm. Recheck for proper torquing of the control arm that you installed and inspect for any other...

Q: When i have my car running with my heat or ac on my car hesitates like it wants to stop when i'm stopped at a light.

As you may know, your car's AC system when working properly puts an extra load on the engine at all times when it is running. When this happens, your car's computer makes adjustments to compensate for this extra load on...

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...
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...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...