AC troubles

cochrank

Well-known member
Joined
Nov 23, 2005
Location
Erie, PA
TDI
2002 Jetta
Group, I am having some AC issues and I was wondering if someone could point me in the right direction. I have searched these post but there are a bunch so if I could just narrow it down. My AC just sort of stopped working. I was working fine and then just sort of petered out. I went and bought a can of the refrigerant. As the directions state I turned on the AC to high and boost (both lights were on). The one fan for the radiator was running like I think it is supposed to do (the second fan was not on). When I went to put the can of refrigerant on to add it, the gauge was reading in the red (over pressure) so I could not add any. I looked and the pulley on the AC pump looks to be turning. I need to mention that when I think it was starting to go out I stepped out of the car and I thought I smelled brakes or clutch burning but do not know if it was from my pump. What should I try first?
 

Hyde7278

Veteran Member
Joined
Nov 11, 2012
Location
Central Mich
TDI
2001 Golf GL
Find the large and small metal a/c lines, beeping carefull touch them with the a/c on. The big ,one should be cold and the small one hot(it can burn you. If there both the same temp then the compressor is most likely not working. If the small line is hot and the large line is not cold you have a blockage in the or five tube or the evaporator. The next thing to do is have a shop put gauges on the system to make sure the charge is correct.
 

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
Also, both fans should be running if the AC is ON. So, the one that's not running has gone kaput. They are prone to get crud in the brushes which results in them hanging, thus no run. And, the resister (internal of the fan motor) on the low speed function is known to burn out.... thus, no run.

If the center section of the AC compressor clutch is rotating, then the Compressor should be functioning. Do as Hyde7278 suggested. Feel of the two metal pipes on the end of the Compressor while in operation. The larger pipe should be cold (not hot) to the touch. The smaller pipe should be hot. As he said, it can burn your finger... be careful. If not, well, there's a possibility that the insulation on the louver doors inside the fan housing (under dash) has rotted out allowing hot heater core air to mix with the cooled air ....... big job to fix.

Lastly, as suggested, a set of manifold gauges will tell you lots of good and bad things about the charge condition of your AC system. A good set can be purchased for about $100.00, give or take a few bucks! They are relatively simple to use! ....... A Google search will be your friend in learning how to use and interpret the information.

Hope this helps!
 

SOOT4BRAINS

Well-known member
Joined
Sep 5, 2010
Location
Phoenix
TDI
2001 golf 4 door 5 speed
I had a similar issue with my A/C last summer. It was cold and then got warm when sitting at a light. Both fans working fine. I pulled over to investigate and found a smell like brakes/clutch. It was the A/C compressor clutch slipping. The highest load on the A/C is when you are stopped and not getting as much air over the condensor. If you have a fan out, this will make the load higher. I could not run the A/C at a stop but it would engage and get cold if I turned it on while cruising. I used a thermometer in the vent to keep a close eye on what it was doing. I re-did the entire A/C the next weekend (compressor, clutch, drier can, expansion valve, all seals) just because it had lots of miles on it but I was able to limp it along that week until the weekend by turning it off when I was going slow/ stopped. Replace the bad fan, I would check the pressures with a set of REAL gauges and if it checks out, I would turn the compressor by hand from under the car. It should have some resistance to it, if it spins very easily its worn out, if it makes any weird noises or feels like it has sharp "catches" as you turn it by hand its likely bad. It should have resistance to it, but be smooth. If this feels ok I would look at doing a clutch.
 

cochrank

Well-known member
Joined
Nov 23, 2005
Location
Erie, PA
TDI
2002 Jetta
Group I fixed my issue. I replace the one large fan that was not working (boy was the motor shot on that one). As I mentioned I thought the pulley was spinning when I viewed it from the top. When removing the belly pan and looking from the bottom I verified it was not. With that I ended up buying a used unit off of ebay and instead of replacing it (having to remove refrigerant and put it back in) I took off the clutch assembly and replaced my assembly. I tried to run it and still nothing. I manually tested the electro magnet and found that was not working either, so I replaced that with the unit I purchased and now it works great. So in short by not having the one fan work it burned out the AC clutch which heated the electromagnet enough that it failed as well. Word to the wise...check your fans.
 

gforce1108

Top Post Dawg
Joined
Aug 2, 2006
Location
Newburgh, NY
TDI
04 Jetta GLS BEW, 03 Jetta Wagon ALH
Word to the wise...check your fans.
That's why there's a 'sticky' at the top of this forum :) Of course - I've had fans fail twice and didn't notice until the AC cut out... The first - both dead and shortly after the coil went. This time, one worked only on low, the other only on high. so hopefully no damage done. Two new fans and the AC works great but I now have massage seats.
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
That's why there's a 'sticky' at the top of this forum :) Of course - I've had fans fail twice and didn't notice until the AC cut out... The first - both dead and shortly after the coil went. This time, one worked only on low, the other only on high. so hopefully no damage done. Two new fans and the AC works great but I now have massage seats.
That sticky is a gem!
Dan says he might re-write some of the troubleshooting this winter.
He's kept up on that thread, answering all the same questions over and over.
 

gforce1108

Top Post Dawg
Joined
Aug 2, 2006
Location
Newburgh, NY
TDI
04 Jetta GLS BEW, 03 Jetta Wagon ALH
That sticky is a gem!
Dan says he might re-write some of the troubleshooting this winter.
He's kept up on that thread, answering all the same questions over and over.
At one point it got un-stickied and I (and I'm sure others) requested it get stickied again. Extremely valuable thread. We just need a 'which battery?' 'low temp in winter', 'should I replace my timing belt' and a few others.
 
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