Skip the auto shop - Our mechanics make house calls

Q: AC blows cold until engine warms up.

asked by on

4.8 liter V8, AC is full of refrigerant, verified with gauges. I cleaned the condenser out with a hose last year when I replaced the radiator. I had the AC serviced last July and they did a vacuum test and it held pressure. They put in .81 lb of refrigerant and it was fine the rest of the summer.

My car has 223000 miles.
My car has an automatic transmission.

You do not mention what kind of vehicle you have, but I can tell you that if they only put in .81 lb of refrigerant then your system is likely low on refrigerant. Most systems take more than 1.5 lb of refrigerant. If you are just using your A/C after not using it during winter time then you may have leaked some refrigerant out.

You should have the A/C system checked to see if it is running at the correct pressures when the vehicle is warm. Depending on the vehicle and outside temperatures, your pressures should be about 30 on the low side and 200 on the high side. These pressures are not exact, and will vary, but would give indication of problems if your pressures at idle are way off from these pressures. I’d recommend having the system checked by a qualified mechanic, they will be able to perform these tests and accurately diagnose your A/C issue. Once that is done, the necessary repairs can be made.

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: I'm hearing a whining noise from the front of the car.

Hi There, Generally speaking there are two things that can make a whining sound under the hood that would depend on the belt and the speed at which it turns. The alternator will tend to make a whining noise when...

Q: AC compressor squeals - 1991 GMC G2500

Hey there. With the engine off, see if you can turn the AC compressor by hand all the way around. Look at the gap between the clutch and the pulley on the top and bottom to see it it is...

Q: My car will occasionally not start

A situation where the car does not always start can be caused by one of several mechanical issues, ranging from fuel delivery problems to ignition system components like the ignition coil or distributor. However, on vehicles more than 10 years...

Related articles

P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
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...