So my wife's car is at it again. At 168k miles, I suppose things are due to break. So far, we have been able to fix many things ourselves (except the clutch replaced at 130k-ish miles which probably could have lasted another 30k miles). I've searched and came across nothing like this.

My wife's 2001 A4 1.8T AC blows cold / hot / cold / hot air every 20 seconds or so. It's weird. First, I thought the temp sensor at the Ac was dirty - so I vaccuumed all the lint that I saw in it. But of course, it can't be THAT easy. So the problem is still there.

Does anyone have any suggestions?

Many thanks, Armand

 

sounds like a coolant flow issue, not sure tho...


one of the techs on here'll be able to help you out

 

If there is overpressure in the AC lines/compressor from being over charged, the compressor will go into a safe mode. On/off/on/off like that. Thats what I found out when I accidently over charged mine last year.

 

Get access to a real vagcom and check codes in the HVAC system. Check the coolant level and make sure it isn't low.

 

Since we didn't charge the AC yet, would this occur if it's "low" as well? Should I try to get it charged?

 

You should get the pressure checked before anything, too much PAG oil in the system, too much refrigerant, not enough, bad a/c switch, and bad compressor could all cause that symptom.
You need to get it diagnosed by someone that is certified to carry out those repairs.

 

^^