Skip the auto shop - Our mechanics make house calls

Q: a/c question

asked by on

A/c button would flash 3x then go off... i figured out that means the system shut down the a/c. I added a can of refrig. and a/c work great... about 3 days later, same thing...3 flashes and nothing. Finally brought to my garage and they said leak. Added new o rings to the low and high valve caps... they charged the system. They ran for 40 minutes on the lot and the a/c was perfect. Brought home and next day, hot day, a/c didn't work...light lit up, but luke warm air conditioning... that night, started car and a/c worked tremendously. That symptom has carried on and off for 2 weeks now. My garaged checked the systme and all the numbers were fine. SO leak seems to be solved, BUT still inconsistnet a/c, cold or hot. ITs' funny cuz as i think this thru, when it works, the temps are not that hot out...on blazing hot days, doesn't work. Any ideas????

My car has 90000 miles.
My car has an automatic transmission.

A: This is usually the result of an electrical...

This is usually the result of an electrical switch in the A/C system. Electrical components are uniquely affected by temperature. Even if the system is full, it can act as you have described. The system may have been low at first, but even a slightly low system should work fairly well.

It doesn’t sound as if the mechanic has had the car while it is failing. There is no way to diagnose a system if it is working, even if it fails under different circumstances. There are several switches in the A/C system that turn the A/C compressor on and off. When the ambient temperature is high, the pressures in the A/C system will also be higher than normal. A mechanic will need to experience this to accurately diagnose the problem.

A couple things can happen to an A/C system when it is hot out:

If the cycling switches are out of specification, they can turn the system off. If the cycling switch gets hot, it will develop an open in the circuit and the compressor won’t run. This may only happen under higher or lower temperatures.

The A/C condenser could be plugged with debris or the fan may not be pulling enough air over the condenser. The condenser is the radiator looking thing in front of the coolant radiator.

The compressor clutch may be getting too hot and slipping. Either way, the only way to know is for a mechanic to catch it while it is failing. If you want to have this checked, a technician from YourMechanic can come to your home or office to diagnose your AC and determine what needs repair.

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: A/C stuck on floor and defrost will not change on any settings

Hello. You need to see if the mode door actuator is working. This actuator is on the evaporator case on the driver's side above the gas pedal. You have to remove the knee bolster for access. If this is the...

Q: How long can I drive if the bearings in the water pump is making noise? car is not over heating and there are no leaks

Hi there. It's not recommended to drive a vehicle with a damaged water pump; especially if the bearings are damaged. If the water pump fails while you are driving, it's possible your engine will suffer serious damage.

Q: Engine made clicking sound, now won't start.

Nothing is more frustrating than thinking a job is complete, just to have a new set of issues follow right behind! Luckily, it seems there may be an easy solution to the problems you describe. A new battery should be...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
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...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.