Strange AC issue, looking for some help
 

I’ve been searching around for some insight on this issue for awhile but I haven’t found much on the web. I’m hoping someone here has experienced this or has a good guess.

Here’s what happening:

On a hot day (75+) when I start the car and start driving around the city (low speeds and RPMs) the AC does not work, at all.

If I get on the highway and get the speed up (maybe 65mph+) and RPMs up (maybe 5k+) the air conditioner starts working fine.

This is the strange part – the AC will continue to work even if I’m back in the city driving at slower speeds again. It will usually stop working if I turn the car off, wait a few minutes, and turn it on again.

This doesn’t seem to be an issue if it’s not too hot outside (70 or less) and seems to be more of an issue (harder to get it working) the hotter it gets.

Any ideas will be greatly appreciated!

I think I've seen couple threads about this issue ... maybe your compressor needs to be replaced?

I would find a shop that specializes in a/c work & have them do a evac & recharge. Could be the system is just low on charge.

If you have manifold gauges I would check the high and low pressure sides of your AC lines. Also do you have any freezing of those lines going on?

Could be low AC pressure, could be your orifice tube, or could also be your Servo flaps. On my car I could rev my car at idle and I would get a bit of AC.

For me it turned out to be my servo's. I still haven't replaced them but I've set the levers manually for now and enjoy happy fun time brisk cold AC :).

Thank you for the advice.

My repair shop originally wanted to replace the compressor because they thought there was a leak inside it, but then later said if it works on the highway it's probably not the compressor.

The evac and recharge seems to solve the problem for a little while, but then it just comes back.

I will ask them about the AC pressure, orifice tube, and Servo flaps. They haven't mentioned those things yet. I may need to get a specialist involved. These guys are good at fixing the rest my car but this issue may be too specific for them.

I will let you know how it goes. Thanks again!

If you have VCDS then you can pull fault codes for servo flaps, if they're bad that is. You can also pull your glove box and play with your hot/cold settings on the control unit. There is a blue one that controls the temperature mixture that get's stuck sometimes (it's next to the big flap that would be next to your passenger's right foot/leg).

Also worst case situation, it could also be your climate control unit itself. Pretty expensive part.