procainestart Dork
8/11/11 12:04 p.m.

My friend bought a sweet, very red, '94 Volvo 240 wagon. She's hot...because the AC doesn't work (BTW, she's married, silly). I'm a nice guy and told her I would swap out the compressor that the pre-purchase inspection report said was dead.

I live in Seattle. We don't need AC much around here (especially this summer ), so I ain't done much of nothin' on one befo'. Before I go get a rebuilt compressor, how can I confirm that the old one is, in fact, dead? Are there any other problems that can act like a dead compressor but be something else? Any tips on AC maintenance in general?


fast_eddie_72 Dork
8/11/11 12:13 p.m.

I dunno a lot, but I did stay at a Holiday Inn Express last night.

I mean, I did fix the AC on my MR2. If there's a system leak, the system will shut down. There's a pressure switch that turns off the compressor clutch. I'm not sure how you diagnose a compressor failure short of it seizing up.

I put some 134 with dye in it. Just enough to get it working. That showed me where the leak was- O-Rings on the compressor manifold. So I pulled it, swapped them out and put it back in. Then hook up the manifold gauge set and evacuate the system with a Harbor Freight vacuum pump. I let mine run for like half an hour. Close up the manifold set and shut off the pump. I checked it after 20 minutes or so and it was still holding vacuum, so I figured the leak was fixed. Then it’s just hooking up a can of 134 and filling it up. This was probably six weeks ago and it’s still working great, so I think I licked it.

There’s all kinds of other stuff that can go wrong, so I got kinda lucky. But that’s what I know.

Ranger50 Dork
8/11/11 12:36 p.m.

fast_eddie is almost spot on as to how I would diag and fix a broken unknown vehicle with A/C problems.

Biggest thing is jumper the cycle switch and see if the compressor kicks on or not. If it does, dead switch. If it doesn't, bad compressor/compressor clutch or wiring. Everything else is a leak source.

A/C maintenance? The biggest thing you can do is to run the A/C system for 10-15min EVERY month.

Woody SuperDork
8/11/11 7:57 p.m.

Where do you find 134 with the dye? Can you get it at the usual pats places or is it super secret A/C tech guy stuff?

fast_eddie_72 Dork
8/11/11 8:12 p.m.

Yeah, at least here they have it in all the chain stores. There's usually a display with all the 134. You have to look through it until you find the ones with dye. Doesn't cost any more than the other stuff. You do have to run over to Ace Hardware and pick up a "Scorpion Light". You need a UV light to see the dye. Apparently, Scorpions glow in UV light. Who knew?

Our Preferred Partners