I may have to concede defeat.

Well, I cannot find any leak anywhere on my 1996 Suburban's AC system, but it clearly loses its coolant overnight. The dye isn't showing up anywhere, and I've had this thing opened up pretty good!

I don't know what else to do, so I guess I'll have to bite the bullet and take it in somewhere and have it fixed.

Any last minute ideas?

EDIT- Sorry, I thought I was in the General section.

Head gaskets?

The leak location you cannot see would be the evaporator inside the heater box. Certain Jeeps and other cars are prone to leak at the solder joints. The compressor seals may be hard to see also.

AC stop leak seems to work well for solder joint and gasket problems... may be worth a try?

That's a pretty good sized leak you have there. I agree with a possible evaporator issue. If yours has rear air then you also have to look at the rear a/c components as well. The biggest cause of GM a/c leaks I see at my shop is the compressor. They will leak out of the front seal, which can be hard to detect without removing the clutch assembly. They also are prone to leak out of the center of the compressor where the two halves connect. Be looking for traces of refrigerant oil on hoses and system components. Don't overlook the check ports on both high and low sides. They are a common leak point. Good luck. Freon leaks can be a pain to find sometimes.

Thanks everyone! I'll look again before biting the bullet and having it fixed. The whole system is nice and dry and clean (no oil spots or grime build-up). Even under the compressor (the bottom) is dry and clean. Yes, it has rear air (the whole reason for buying a Suburban in the first place).

Very frustrating indeed!

Just about every time I had an evaporator leak, I could find the dye in the drain hose. (In case you haven't looked there. )



Tim

I haven't! Thanks!

I am with you on the rear air. Glad my Durango has it. But around here, rear seat warmers are the big deal. Drove to North Dakota without them in a rental car and never heard the end of that.
Craig

We have the rear air for our two big dogs. They won't fit in the back of a Durango, or we'd certainly own one!

The Dakota we had used a topper, but it was hot for the dogs, so we got the Suburban.

'Tis a pity that Dodge never got around to it after the early '60s. My '93Sub had rear air but not rear heat. On long winter trips the rear windows would be all frosted over after an hour or so, no fun for the passengers. But any time we traveled it seemed like the right tool for the job. One kid and the dog in the middle seat, the other kid in the back seat. Everyone could stretch out and on really long trips the driver could sleep in the middle seat while other driver and kid were up front. It was a flying living room.

IF you're taking the whole A/C unit apart, there is a motor that opens the vent door, the one that goes to the outside. You may want to replace this motor while you have a chance. It's nearly impossible to get to it without disassembly, at least it was on my '93. Sometimes the motor would malfunction and it'd go flap flap flap for the longest time.

R.

You probably already checked these, but if you can vacuum it down and it holds vacuum, then a Schrader valve might be suspect. Everything looks good until you remove the gauges and then one of these valve leaks.

After not being able to locate any leaks, I got another dye set (this time UV) and loaded up the system again. Funny thing is, it stayed cold, I even took my dog to the vet and back this morning and it was nice and frosty in there! It's hot here, too!

So I was a bit hopeful it may have "corrected" itself, but alas, no. I went to get some take out BBQ tonight, and it was not cold at all. So at least I was able to run the system for about an hour and a half with it working. The dye should be well circulated, and when the sun goes down tonight, I'll have another look!

You guys were right! The compressor bottom and all around it is glowing with dye! No oil, no nothing, can't see anything without the light. But using the light, it's one big green mess! I checked everywhere else, only found a trace leak in a line that runs to teh rear. A quick look thru youtube found several indicating that problem and the repair for it.

Time to go shopping!

Thanks again everyone! And thanks for being patient with me posting this in the wrong place!

Dang chivvy guys.



Glad you found it.



Tim