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clutch engages, no leaks, blows warm

mccarthy_mg on Sun March 23, 2008 8:55 AM User is offlineView users profile

Year: 1995
Make: VW
Model: Eurovan
Engine Size: 2.5L
Refrigerant Type: R134a
Ambient Temp: 70
Country of Origin: United States

My A/C stopped blowing cold. The radiator fans and evaporator blower work, the compressor engages. This wasn't the first thing I checked but eventually I got around to letting some R134a out of the system, and sure enough the compressor clutch stopped working. I added some back and the clutch started working again. So, there is at least enough pressure to activate the clutch cut-out switch.

It's a VW with a typical system layout The high side starts at the compressor discharge, then goes directly to the evaporator, then to the receiver-dryer (the r-d inlet has a blow-off valve, the r-d outlet is plain). Then, the circuit goes to the aforementioned cut-out switch and then to a "Y" where it forks to both expansion valves just ahead of the front and rear evaporators.

I'm going to skip describing the low side, because I have a question about the high side.

I have two similar VWs, one a '93 and one a '95, and they both have similar A/C systems, and it's the '95 that has stopped blowing cold.

On my '93, which works well, if you touch the lines on the high side they are all hot. The compressor discharge, the in/out thru the condenser, and the in/out thru the receiver-dryer...everything on the high side is hot.

On my malfunctioning '95, the compressor discharge line from the compressor to the condenser is hot, and the condenser is sorta hot, but everything after the condenser is cold. That is, the condenser outlet is kinda warm, and the in/out thru the receiver-dryer is stone cold. I think something is wrong right around there.

Could the receiver-dryer be bad? What are the symptoms of a bad receiver dryer? Could the compressor be bad?

It was working great the last time I used it, then all of a sudden it wouldn't cool. Thanks for any help.

(I have a cheap gauge, and I was hooking it up to both the '93 and the '94 to compare pressures, and in the process the membrane in one of the valves on the '93 tore and started leaking, so now I have to keep that system sealed with just the dust cap and will now have to replace the valve. It's been one of those days. It started with both A/Cs working and it ended with one not working, and one that could fail any second. I don't want to mess with pressure readings again unless I'm in a shop with better set of gauges. I'm assuming my cheapo gauge tore the membrane, but I'm not even sure of that.)

Dougflas on Sun March 23, 2008 10:37 AM User is offline

Recover the charge, evacuate, and recharge by weight. Then at least you'll know the refrigerant is not the problem.

mk378 on Mon March 24, 2008 9:51 AM User is offline

Your van most likely does have a leak. As refrigerant is lost, a TXV system will quit cooling long before the switch finally drops out. Get a good set of gauges so you can see what's going on. And you have to ensure that it has a full charge by weight before much can be diagnosed.

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