I'll run the dye through and see if I can find a leak somewhere. How long does that dye stick around?

I know the cans around here range from $5-20 for a 12oz can of freon. It's not terribly expensive if I'm just testing for pressure before taking it for a proper recharger.

Is there a diagram floating around? I was tracing the AC lines and some of them seem to disappear in the engine bay. I googled and searched the forum and found all kinds of information.. but none for the disco 2.

 

Or invest in a R134a manifold & vacuum pump for troubleshooting and serving. Easier and more forgiving than many other repairs or service items recommended to DIY. Likely pay for the equipment after one or two leaks, refills or top offs of your LR and other vehicles. Professional AC service doesn't often come cheap.
......

 

Do you have a copy of the RAVE Workshop Manual? If not, download it from the link in my signature below and look at the air-conditioning section. It's all right there.

 

I do have a copy of the rave, I didn't think to check there. I will check that before I add the dye.

I bought a can of dye and a uv light this morning. I'll run it through around dusk and see if I can get a fix on the leak.

 

If your truck is a 7-seater with rear air remember there are lines running to the evaporator in the rear behind the panel next to the left jump seat. For some reason the rear system illustration is 20 pages after the primary A/C component layout picture.

 

My truck is a 5-seater so no rear air condition and thankfully no air ride troubles to deal with.

Anyway, I put the dye in. To my dismay, two things occurred: no obvious leak at all and the system at least has some pressure. I didn't get a good seal on the fitting when I first pressed it on the low side and I could hear/feel pressure escaping. So now I'm really confused.

I was really hoping to come back and post some pictures of a gaping hole somewhere. Sorry to let you down fellas.

 

Perhaps you did this but in case you not, you have to run the system for a while after you add the die. If the compressor is not turning, the die will not be circulated through the system and you will not have enough pressure to force it through the leaking seal.

 

Before you run out and buy a vacuum pump and manifold, autozone does "loan a tool" them, not everyone Autozone does, I would call one first and see if they have one to loan, of course that is saying that you have an Autozone near you. My AC had a slow leak, it was basically empty when I got it, I replaced the o-rings on top of the compressor since they are easy to get to, and the compressor o-rings fail often, and it did fix my problem, ran a vacuum on it with the Autozone stuff for 1 hour, shut off the pump and it held the vacuum for an hour, then recharged it, its worked great for about 2 months now.

 

I did cycle the system for probably 15 minutes while looking for leaks. I could not find dye permeating through anywhere.
I did, however, find that the compressor is leaking right where the two halves of the casting come together. I found it with soapy water. There is no dye coming through but it is creating bubbles. So my guess is that it is compressing air and leaking it back out before the system makes a full loop.
I will call up autozone and see if they have the manifolds to rent since I don't have any way to measure the high-side pressure. I do have a couple of psi of low-side pressure.

So the compressor seems to function. The clutch engages, engine RPMs increase, and the compressor gets warm (and you can feel it "doing something"). I'm guessing that main gasket in the center of the housing is no good and is leaking anything that is getting compressed by it.

When explaining this to a friend of mine, he said, "just sell it." ... because this could potentially cost about half as much money as the vehicle is worth around here.

 

If the compressor is leaking, replace it and recharge the system. I wouldn't sell it over that.