Replaced all the gaskets including the front condenser one that you have to pull the grill to get to, still leaked out.
I even tried doubling up in the receiver dryer gaskets, the leak slowed, but all the freon was gone by the morning.
At my wits end.
Are there any plastic collars or o-rings on the blocks that bolt to the receiver/dryer?

 

I am not sure if yours is the same, but there is an oring on the high pressure relief valve on the compressor and check to see if your relief valve has gone off. They tend to leak after they do that...Mark They will also hold a vacuum, then leak under pressure...

 

It has gone off many times. I thought the pressure relief valve was on the receiver/dryer... I will look for the one on the compressor.

 

On my '90, it is on the compressor, I am not sure on the later trucks. When they do go off,, they tend to leak and as I said before, there is also an oring on it...Mark

 

I would charge it up with some leak detection dye. Mopar part # 047982AC for R-134a. Use a black light to see where the dye is coming out at.

 

I did. The pressure relief valve on the receiver/dryer was leaking.

 

Looks like maybe the vsle is bad? You can clean it possibly. Make sure you have orings if it needs it. Over night is a big leak.
you should be verifying it holds vacuum prior to charging. Least 1/2 hr.
this is an early truck w the pressure releaf.. pre intercooled.
There was no electricity fan, so be warned head pressures will soar when stuck in hot weather slow traffic.
m

 

All leaked out again, even with a new receiver/dryer. Don't know where to turn from here.

 

Is it still leaking from the same spot after replacing the drier? Doesn't make sense. There is no excessive pressure there with the engine not running. You must have a leak elsewhere. If you can't see it, it's most likely the evaporator or front seal on the compressor.

​​​​​​​And why has your pressure relief valve gone off many times? I live in Florida and mine has never gone off. You either have a bad fan clutch or its way overcharged, or both. What are your pressures reading?

 

Update, after much leak detector and changing every gasket several times over, finally borrowed a brand new Snap-on freon leak detector, and although I never saw an UV dye around the compressor, but according to the meter the compressor is a sieve.
Can't afford to replace it until spring, but at least I have heat now!.

Any advice on what to look for in a new compressor, anything to stay away from?