I'll try to describe it as best as possible. I want to do as much diagnosis as I can before I end up taking it to a shop and paying the $70 diagnostic fee.

2004 1.8T Jetta 5-spd. 80k miles. Bought the car in Feb, so even with the A/C on if it didnt work, i'd still blow cold air. Now that NC air is getting warmer and warmer, I'm starting to realize the A/C isnt working. When I first noticed it, it blew "kinda" cold air, but nothing amazing.

When you press the A/C button on the dash, the car comes under load as if the compressor is coming on, and the air is a *TINY* bit less hot, but not "cold" by any means. Even with recirculate, nothing major, just hot air blowing. One of the electric fans runs during the process, but not the other.

Thought it may just be low in r134, recharged it with 18oz of 134 w/stop leak. PSI for the air temp that day said between 25-30, and got it to about 28 and called it a day. Didnt use the whole can. A/C blew pretty cold for a few days, then back to hot sweatbox. Recharged it with the rest of the can, never could get it above 30psi. Blew cold again for a day or so, then nothing.

That was about 2 weeks ago, now when I press the A/C button first thing in the am, the system makes kinda a "wheezing" empty sound for about 10 sec and then blows warm air. The whole time the system runs it makes sort of an "empty" noise as if the refrigerant is low, however its reading just above 30psi now (warmer outside temps recently). You can touch the condenser around the low side port and its not cold, and you can touch the high side tubes and they are not hot (like they should be right?).

Now I've read that several people have found fuses blown, or control modules scewed up on their cars. I want to try and eliminate all possible "simple" fixes before I take it to a new level.

Anyone have any other place to start? I'm dying in this stupid car.

4/13/2011 4:09:49 PM

sounds like the same symptoms i had in my 98 cherokee about 5 years ago. ended up having to replace the entire compressor.

4/13/2011 4:15:05 PM

You've mentioned a lot of the obvious stuff. Check the fuses, make sure the cooling fans come on (on VWs both should when the AC is on). Check to be sure the clutch on the compressor is engaging. Look at the center of the pulley on the compressor- it it isn't turning, the clutch is not engaging.

4/13/2011 7:03:48 PM

What Mappy said.

1. Verify that the compressor is running first and foremost.

2. Refrigerant with stop leak and that extra cool additive is damn near useless...and if it has extra oil in it too, then the more you put in, the less efficient your system is. I stay away from that shit like the plague. Some of it has methanol in it...and methanol is corrosive over the long haul...and even if it temporarily stops a leak, it grossly shortens the life of o-rings and seals.

3. If you're only charging it based on lowside pressures, then you're charging blind. At the least, you really need to monitor high side pressure as well. Differential between the two can tell you VOLUMES of info. You can charge to what looks like the correct pressure on the low side and end up with too much on the high side.

4. The only properly charged AC system is one that's been evacuated completely and recharged with the correct amount of refrigerant by weight...

I know that you want to avoid the big expense of having a shop do the service, but my advice is that you might want to leave this up to a good tech.

BTW, I am certified, lol...

I'd say it's highly likely you've got a nice leak somewhere.

4/13/2011 7:19:23 PM

^You want to take a look at it sometime next week then? With temps not topping 80 for the next 7 days, it isnt such a rush, but I know those 80's-90's are coming.

4/13/2011 8:28:02 PM

Well, took it to a shop and had the A/C recharged properly, was ICE cold when I left yesterday afternoon. Was sort of "melty ice" cold this am, and this afternoon, the wheezing sound is back and its blowing seriously hot air.

So this means good and bad right? The compressor must be good, because it cooled once it had the proper level of coolant in it. However, now I must have one hell of a major leak. I had the tech put some leak finder/sealer in the system in case it did have a leak, so I'm hoping to find some red dye at an easy to fix location.

Crap, hot as hell. Hottest day of the year so far, I had to dress up for a mock interview, and the goddamn A/C is being a retard. Shoulda drove the Tundra today.

4/20/2011 4:54:06 PM

Yessir, you definitely have a bit of a leak. None of the regular sealers work very well, especially for any kind of leak that isn't o-ring or rubber seal related. You can get another type of sealer that works reasonably well for hose leaks and the like, but even it doesn't work all that well.

For R134 leaks, due to the ease with which it leaks, the only type of leak detection dye that works worth a damn is UV dye. Are you sure that's not what the tech put in it? Any other dye requires LOTS of leakage to find anything, and R134 won't leave that much of a trace. Even UV dyed leaks can be hard to find.

Best bet is to use a sniffer type leak detector...either a heated diode type (more expensive, but finds R134 leaks the easiest) or a corona discharge type (what I have; works fairly well). With a leak like you're describing, it won't be hard to find with either.

One thing about R134 in relation to other, older CFC style refrigerants: it leaks faster, much easier, and leaks are harder to find. It's damn near the bane of an air conditioning tech's existence.

4/20/2011 9:35:52 PM

^Well shit, that blows. Hmmm...damnit.

Edit: I dont think he put in UV dye, but I'm really not sure. He just said "leak finder".

[Edited on April 20, 2011 at 10:10 PM. Reason : .]

4/20/2011 10:09:59 PM

I'd bet money it would have to be. That's the only thing anybody uses anymore. The old red stuff went out of style quite a while ago.

4/20/2011 10:57:25 PM

I delt with a bad compressor last year. Tried to save some money and do it myself and internet parts.

Lesson learned, AC is one of those things you need some specialized tools and skills that you hopefully wont need frequently. Take it to a shop and have them fix and diagnose it, so you have a warranty when shit breaks.

4/21/2011 7:15:16 AM