jcesquer

I currently drive an 2005 Audi A6 3.2l C6, everything is fine but the AC.

Sometimes blows cold air when im parked at a red light.... but while running, it only blows hot air.

Any suggestions of what this might be?

Some AC experts say that its the compressor, but i still have my doubts about it.... if it is the compressor, it will never blow cold air at all... right?



Please HELP!

roylok

Hi, I don't consider myself an expert and such in car A/C systems, but I do have 10 years of experience with residential A/C units. The same principles apply to both systems. Unfortunately from what you described it has to be the compressor, or something electrical causing the compressor to kick on and off. A clogged coil, low refrigerant or impurities on the refrigerant would cause poor performance, or you won't get any cool air at all.
IS the compressor belt driven on the 3.2? could it be that the belt it's slipping on higher revs and catching on low revs at the stop light? (A loose belt on my beater's alternator a few years back would charge the battery only when the car was idling, funny right?) Maybe a real expert would have an answer

jcesquer

Thank you for your quick response Roylock.
Ill verify the belt tomorrow.

ProtoFly

Is the hot air mostly from the side vents? There's some known issues with the HVAC system, specifically a valve assembly which gets gunked up, which can cause hot air to come out the side vents.

Although I can't find the DIY (My google-fu isn't apparently up to par today), there's a DIY somewhere here about how to clean the valve, which has apparently saved people some significant $...

jcesquer

thank you for your help. It blows hot air from every single vent. I was looking for this DIY file but I can´t find it anywhere.
Someone knows the link for this file?

Trekie

Unfortunately it's the compressor. I had the exact same issue with my car. The day the compressor failed, it was funny because the AC was ice cold, I stopped at my mechanics shop to get my oil changed. When I left to go home, the compressor failed.

eazy211187

You'll need to replace the compressor.

newa6er

Gee, that dont seem suspicious. Did you use the oil change guy to fix the AC compressor?

Trekie

Yes i did. The owner of the shop is a personal friend and lets me use his lift to do my own oil changes so to answer your question, there was no foul play.

Prospeeder

Not enough information. DO NOT just go replacing the compressor. You need gauges hooked up and see what really happens when the a/c stops working. It could be the system is low, compressor is being told the turn off for some reason, the compressor is variable so the mechanism inside could be bad, theres a expansion valve, the entire electronic HVAC system with flap doors and what not. Theres ALOT more to it than just replace the compressor.