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.

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
  1. Home
  2. Questions
  3. a/c question

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: When a car overheats does it leak out refrigerant?

Your car's air conditioning system is an entirely separate system from your radiator and cooling system. As such, it should not be leaking refrigerant when the vehicle overheats. Typically when a car does overheat and begins to leak fluid, it...

Q: car wont start.

Hello, thank you for writing in. Low or no compression in the cylinders can be cause by several issues. If the starter is turning too slowly, the air is able to escape through the gaps in the piston rings, and...

Q: My truck is running sluggish

Hi there, thanks for writing in. If the engine had non-fouler plugs in it then you need to do a compression test. If the engine is worn then it will need these plugs and may not be able to produce...

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...
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...