Hello all. Good morning from NYC!!! With a photo of a visitor from the U.K...

I have another thread where I recieved lots and great pointers on the restoration of a 1990 XJS Convertible A.C. system... In the end, I could not get the required 12v to the compressor relay from either the A.C. ECU or the dash control switch, or both. A measly 3.6 to 5.1V... Not wanting to purchase a tough to find A.C. ECU I settled on rigging and wiring a dedicated 12v source and toggle to the relay from the easy to find white wire that runs throughout the vehicle supplying 12v to other and many relays. It worked. Better, it works for now, lol.

I had to completely disassemble the Compressor and replaced seals and rings. Also replaced rings in the hose connections I could find.

So, I vacuumed lines, it seemed to hold 29 lbs of negative pressure overnight x2 or 3... I filled it with r12 and it blew a cold 39-42 degrees for about 10days. Seems i have a leak

Before I dive back in I have a simple question about compressor O-rings... From all y'alls experience, is there an o-ring in the shaft of the drain plug of the A6??? I didnt find or change it during compressor rebuild (yup - dumb ***)... Is it deep down in the shaft??? I have a dye, a light and some cheap cans of 134r I plan on using to partially fill the system in search of the leak. Yes, the system has a good distributed supply of mineral oil in it,,, so I think I'm good there,,, but before I do this I'm wondering if it would be best to dig out the whole compressor and find this ring if there is one. For some reason, I have a feeling that's where my problem lies.

Deep bow and thanks in advance for any and all guidance, info, suggestions and advice.

 

What I do for detecting leaks is I have a hydrocarbon gas detector (TIF model 8900) that is good to 5 ppm of methane. Then I have made an adapter hose that goes between my BBQ propane bottle and the charging port of my AC gauge set. With the cars AC system evacuated I charge in propane to take the system to around 10-15 psi with the engine off.

Then I go around each joint with the gas detector and I can usually find a leak very quickly. Propane is heavier than air, so simply run the sniffer under each joint in the entire system and you will soon know where you have a leak. It might take some playing with the sensitivity of the meter to get the right amount of detection for the size of leak you have, but I find it much faster than dye.

Then instead of guessing about where you have a leak, you know. Then you also don't charge refrigerant into a leaky system, and the cost of the propane is only a few cents per test, as it doesn't take much gas to get it to 10 psi.

 

sounds great,,, thing is I dont have a methane detector... and it looks like they cost hundred$$$

any ideas about the o-ring in the tube for the compressor oil drain plug?

 

I don't think so, but it's been so long since I looked I can't remember. A more likely place for leaks is the fill ports themselves, especially if you have R134 ports retrofitted.

It's critical to have the hoses on the back of the compressor seated squarely too. The plate Jaguar used is fairly thin and bends when the bolt in the centre is tightened. Then the hoses are not held square onto the O rings. The plate from early 70's GM cars that used the A6 is about twice as thick, I always replace the Jaguar one with the GM one if I have an AC system apart. They are getting harder to find now, I got mine from self serve junkyards, but the supply of GM cars has dried up around me. Easy enough to make though, it's just a plate of steel with a hole.

 

Hi JagBoi... Thanks for the heads up. I have replaced mine as well. Thick heavy thing.

I've tried to find o-ring diagrams of the A6 but never one that details what is going on in that little section of drain pipe... The "kits" supply rings that are about that size but I was just not paying right attention when I did mine to see if there was a ring in the tube. Feeling a bit foolish now,,, but still,,, if I don't have to I don't want to have to remove the entire compressor unless I am sure there is an o-ring to be found there.

 

The little oil feed pipe between the sump and the pump has a little O-ring... Not big.

 

Yes D. Thank you.... I got that one. On the left hand center side of the picture is the little ringed tube that goes down into the oil sump/well... I did replace that ring. Sat snug and well into its slot after...

Still, Im trying to find out whether or not I need to pull everything apart again (pull the compressor) just to dig out an o-ring I don't know exists at the sump drain plug... Looks like whether an o-ring is there or not is a mystery...

 

No ring/washer at the sump plug. It has a copper washer on the outside on some of them...