Skip the auto shop - Our mechanics make house calls

Q: My AC

asked by on

When I first start my car and turn on my ac it always immediately blows cold til about 15 to 20 mins after, it'll just start blowing regular air, it'll stop blowing cold. When I cut the car off for a while and start it back up it blows cold again until about 15 mins so I'm not sure what the issue is but it's starting to get really hot here in Houston so this has to be fixed asap. Please help. BIG THANKS!!!

My car has 148000 miles.
My car has an automatic transmission.

A: The evaporator is freezing up due to over-c...

The evaporator is freezing up due to over-cooling. There is a thermistor on the evaporator (behind the glove box) whose function is to prevent the surface of the evaporator from getting below 32F and icing up. It should be cycling the compressor off, but your’s doesn’t. When the evaporator ices over, the A/C gets warm. After the ice melts, it blows cold again until it ices again.

You need the evaporator thermistor tested and probably replaced. If you need help with this, consider getting some assistance from a qualified mechanic who can diagnose your A/C issue and replace your thermistor if necessary.

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: My car alarm is going off for no reason

Hi there. Check the sensibility of the car alarm. If the car alarm is set to a slight vibration and can pick up light vibrations, then check around the garage that would contribute to a light vibration. That may be...

Q: Abs light randomly coming on. Sometimes can't get the lever out of parking.

This may be an issue of a faulty ABS control module. This is a unit that controls the activation of the ABS system based upon inputs from the ABS wheel sensors. When this module is not working properly you may...

Q: The gear shiter is stuck in park I have to manually shift it and the brake lights don't work.

Hi, thanks for writing in. There are several causes for the symptoms you are having. First, if you need to unlock the shifter, there is an override button you can use to unlock it. It will be a small slot...

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...
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...
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...