Hello

My 01 b5 a4 2.8q has not been blowing cold air since i bought it from its previous owner. It does blow hard but its not cold in any sense of the word.

One thing i noticed was there was some liquid (greasy?) building up on the bottom of the windshield.

When i checked the ac pressure with those refill kits, it was in the right pressure range, but on the high side.

When the engine runs and the ac is switched on, the clutch for the compressor kicks in and the rpm drop is there.

I drained the system's refrigerant and refilled it with r134a. After some driving and a/c usage, it is very insignificantly colder, but its still blowing pretty much room temperature air into the car.

What can i diagnose next? Anyone solve anything like this?

 

Does one of the aluminum pipes going through the firewall to the evaporator get cold? If you have pressure in the system and the compressor is on, one of the pipes should be cold. If so, something in your airbox or AC control head is bad. To diagnose that, see this article.

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Neither of the pipes get cold. The clutch engaging is very audible though.

 

I'm not sure what's going on. If the compressor is good and there is 134a in the system, one of those pipes will be cold. If there is no 134a in the system, the high/low pressure swith won't engage that clutch to protect the compressor. Almost makes me wonder if that clutch is bad....but if you say you hear the RPM's drop; that clutch is engaging the compressor.

 

Actually, just checked the AC today (3 days after refilling the refrigerant) and its pretty cold at the LO setting.

However, as i move the temp up towards hot, there are a bunch of weird noises and compression sounds... hard to describe but it doesn't sound too good. sound fine when its kept at LO though.



edit:

was blowing cold first thing in the morning.

no longer blowing cold in the afternoon.

 

Have you gone through the diagnostics here?

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