The A6 has a sump, you can just pull the drain plug.

 

There is another kind, based on a Nippondenso compressor. Something like this: S6 Automotive Replacement Airconditioning Compressor Product Features

I have one in the garage, but never used it as I sold my older V12 cars before I got around to converting the compressor. I got it at an Agricultural AC supply, as I gather many tractors over the years have used the A6. At the time much cheaper than any of the vintage AC places.

 

Thinking about what would be perhaps the best next step before I consider when or how to do a Sanden upgrade or r134a conversion...

...might it make sense to next weekend just replace the O-rings at the compressor and then pull a vacuum to see if that is the only leak? If it leaks at the expansion valve or some other hard to get to point, it might alter my plans.

 

Good place to start before introducing unknowns.

 

Mac, in principle, it did. The large OEM steel bracket that bolts the actual compressor to the engine may have had to have the holes enlarged or altered a bit to fit the compressor, but nothing more than that. The bracket is slotted where it attaches to the engine, so aligning the belt is no problem at all. Same belt and pulley used. The Sanden is miles better than the old OEM lump, aircon really transformed. You must fit a new dryer unit when you redo the system. If you need a photo, let me know. Electrical connections just the same apart from splicing the connector into the line. It is just a live feed that is switched by the Delanaire unit in the cabin (green wire from memory), and an earth wire.
My aircon guy fitted modern kind of press-on-type fittings to the back of the compressor, so that his aircon gassing machine just clips straight onto it for gassing and de-airing the system. These fittings also just allowed the OEM hoses to bolt straight onto them. All quite straightforward.
Greg

 

Thanks to everyone for their generous help.

Unless someone disagrees, my current plan is that since the system is completely leaked out, I think I should replace all the O-rings, and I'm going to replace the Dryer because they are so inexpensive.

Once I've got that done, then I can pull a vacuum and see where things stand.

Is there a way to know where all the O-rings reside?

Should the O-rings be lubricated before install? And with what if the answer is yes?

Thanks

 

Basically O rings will be found at each joint. See the diagram here: Refrigerant Hoses-5.3 Litre - Parts For XJS from (V)179737 to (V)226645 | Jaguar Heritage Parts UK

Make sure you double wrench each joint, so the pipe the nut is attached to doesn't move and twist the rigid pipe. Be extra careful at the expansion valve on the firewall. Going from memory is has flat sides that a wrench can fit onto to hold it stationary. A wrong move at the expansion valve can have the evaporator pipe crack and that's a dash out job to replace.

Lube really isn't necessary, but a bit of mineral oil on the O ring will allow the nut to slide over it a bit easier. Can't hurt anything.

As an idea, is there a "self serve" junkyard like Pick n Pull near you? Maybe take a few wrenches and pull apart a few hoses on cars at the junkyard just to get some practice and see how they typically go together? AC fittings are quite standard, take apart anything domestic with threaded connections from the 80's or 90's and you'll have a good idea of what you're dealing with. Some Fords have quick connects, ignore those. Might as well break a car going to the crusher rather than your car...

 

Mac, I honestly think you are kidding yourself. The compressor will be shot, or at best really worn and inefficient. By the time you have messed about with the O rings etc etc, you would be better to wait until the funds are saved up and then just replace the compressor, expansion valve and dryer. Then do a vac check (or these days the aircon guys do a nitrogen pressure check which is much quicker and better) and take it from there. Unless your evaporator core is shot by ham handed removal attempts on the under bonnet hoses, the system will freeze you easily.
When I did all this on my system (on a system that was actually working) the difference in the effectiveness of the system was night and day.
Greg

 

Why do you say that? The A6 is known for being a very tough compressor. Not the most efficient, but incredibly tolerant of abuse. As long as there is oil in it, it should be fine. This comes from experience of swapping compressors I got from the junkyard!

 

Well, I am a kidder (I kill me...haha).

Let's not get ahead of ourselves and remember I'm still on training wheels and anxious to learn how to do this rather than just take it to a shop.

The way I look at it, O-rings are generally an easy straight forward thing (expansion valve excepted), and would be an relatively easy first step in getting to know the system. If some of the O-rings are hard to reach or I think I might risk doing damage, I might leave them for now, and see how the system tests.

The system is empty, and the car is 26 years old, so new O-rings can't really be a bad idea...? New schrader valves and dryer too.

I can eliminate them as the cause of any leaks, and see if the system holds vacuum or unearths some other problem(s).

Before I get too far into this, I'd like to know if the evaporator or condenser are leaking, or the compressor is shot, or the expansion valve, etc. Knowing that will help me determine when (or if) and how I'd go about attacking the problems.

My limiting factor isn't money, but time and knowledge.

 

Mac. Aircon is specialist, which is the only reason I suggested using an aircon guy, as a few score dollars with a specialist will give you your answers in about a half hour. If you have the equipment to test pressure or create a vacuum, then go for it. In which case I would try to do it section by section.
The condenser and the dryer have screw fittings, so can be tested as a unit with the dryer or separately. The High Pressure line from the condenser to the evaporator runs up the USA passenger side lower chassis rail and goes via the expansion valve to the evaporator. You could connect to the HP at the condenser end and after the evaporator core at the joint where the Low pressure return flexible attaches to the fuel cooler above the USA driver's side inlet manifold. This would test the evaporator and the lines and their O rings. So the leak would be identified to a given part or parts of the system.
The big black flexible hoses, if they are the originals, will actually not hold the modern refrigerants - believe it or not the molecules percolate out by wriggling between the actual molecules of the old OEM hose material! So new hoses of the correct stuff will be needed if this is the case.
Finally the compressor would be left. The most vulnerable part of the compressor is the seal on the spindle to which the pulley is attached. Not using the compressor regularly causes this seal to dry out and then the thing leaks and nothing to be done but replace it.
Greg

 

Hey, I knew nothing about aircon a few years ago and I got my system running, even went as far as repairing a hole in the condenser which everyone said couldn't be successful.

One tool you should not be without before haphazardly replacing everything!!

A strong UV light.

eBay is a good source, get a 21LED UV flashlight, these are super bright and very affordable. Look at your ac system in total darkness. Usually UV dye would have been added at some point, if not, put some in.

The leaks will show up bright as can be, no more guessing as to where the gas leaked out!

good luck,

Larry

 

Just a quick update to the thread.

Had a chance yesterday to tinker with the XJS. Replacing O-rings turned out to be a good idea, as many were perished or brittle. In fact there was little evidence that the two where the hoses connect to the compressor were ever there.

After replacing the dryer, and the engine bay O-rings, I decided to pull a vacuum just to see where things stood. It appears that the compressor itself is leaking at the front shaft seal, which I understand is quite common.

I also found out that even though the A6 is a tank, it apparently isn't well suited to cars that aren't regularly driven. If the AC isn't used often enough, the shaft seal will fail quickly, which has become a problem with vintage GM muscle cars as prices rise and people don't take them out regularly. Though I drive the XJS regularly during top down weather, it does go through periods when I won't use it.

Because of the above, I'm inclined to switch to a Sanden rather than attempt to rebuild/reseal the A6 or get another A6 since my usage patterns will likely guarantee another failure.

At least that's my current thinking.

 

Mac
Many congrats on narrowing down the problem and fixing the leaks. However, the front shaft seal will dry out if the aircon is not used regularly, say at least once a month, better a bit more, regardless of the make. The front seal relies upon regular oiling, which happens through the compressor being used, to keep its integrity. Just a matter of starting the car, aircon on, and letting it tickover for 15 minutes every so often.
Greg

 

Yes that is my understanding, but also got the impression that the A6 was particularly vulnerable or would fail in this manner sooner than the more modern designs.

 

Greg in France,

If it isn't inconvenient for you, could post a photo of your Sanden installation?

Thanks very much.

 

No bother
Greg

 

Greg did you remove your cruise bellows?

 

Yes, when I did my rebuild I ditched the cruise control and all associated loom and bits. V access and plug changes are much easier now. Incidentally, the Sanden is smaller in diameter than the old OEM A6 Harrison, so changing plugs A1 and B1 is considerably easier.
Greg

 

Yes, I've been tempted to do the same, but I've kind of been on a gig of trying to make everything work as it should, so not sure on that. I imagine the lack of the bellows improves air flow and helps to keep temps down in 'death valley'.

How did you deal with the High Side Low Pressure Switch? I can't see one on the schematic of the Sanden U4646, did you add one, or eliminate it, and just wire the clutch to ground?

Thanks.