Hello all,
I have been so busy working on my two Series 3 Jags and on top of that doing needed stuff on my Volvo, Equinox and Eldorado that I forgot to post results of my previous issues.
However, another issue just dropped in my lap.
I believe I previously mentioned that I was working on the AC system on my running '84.
I replaced the EXP valve, thermal limiter all O-rings and the dryer, and took it to an AC shop to get it evacuated and recharged with R12.
3.4 lbs of R12 @ $50.00 a pound plus service fee of $75.00.
The shop hooked up the machine and with my own eyes I saw the system pull down a vacuum of 30 in Hg for 45 minutes and after turning off the machine it held the vacuum for another 1/2 hour.
The tech put some dye in the system and went ahead and recharged the system with the R12.
With the AC unit now blowing BEASTLY cold, we ran the car for about 20 mins, to see how the engine temperature would respond with the AC system active. Everything was normal.
I happily paid the guy and drove the car home.
About five hours later, I decided to take the car on the freeway and low and behold, the AC is no longer cold, not even cool. I looked at my heater valve and it is in the "UP" position and looking at the sight glass on the dryer, Nothing.
I drove back to the shop, and the guy basically told me that I have a leak in the system and he used a light that shows up the dye and found no leaks at any of the connections and components in the engine compartment and suggested to me that it could be my evaporator that is leaking and if I replaced it he would work with me on the price of the recharge.
Fearful of the amount of work required to replace the evaporator, I decided to pressure test the evaporator before I tore the interior apart.
Using my old expansion valve I rigged up a system to pressure test the Evaporator.
Pic 1 shows my air supply and the rubber stop (held in place with a small C-clamp) I used on the side where the low pressure hose is connected.
I flushed the evaporator and put some strong smelling acetone and applied 40 psi of pressure. The evaporator held this pressure until I stopped working.
I turned on the AC fan and no acetone smell in the car.
Given the above I believe that my evaporator is not leaking or that the 40 psi was not enough. Any ideas?
Today, I am going to break up the system in sections and pressure test each component.

 

Do you have any friends that do house ac work? If so have them.fill it with nitrogen, they can take it up.to the pressures that your system will be at, and.they have sniffers.to locate the leak, but to lose that much freon that quickly you ahould be able to see where it came out, although freon is invisible, the oil in the system isnt!
The old test for gm was to stick finger in the evap drain hose and see if it was oily. Freon also burns green making it easy to find with propane torch with small rubber hose at air inlet , however it produces phosgene which is poisonous, probably why they stopped doing it!
Cheapest way will likely be a home ac guy. Good luck!

 

I wouldn't take it apart yet...


Fill the system with 120PSI from a standard air compressor through the scrader valve and then use soapy water from a spray bottle to find a leak. Shake components by hand to simulate driving like conditions and vibrations.


I've been working on A/C system for 20 years and tried all the dies and sniffers, I prefer air and soapy water. This low cost environmentally friendly technique has never failed me.


You can run the A6 for a short while to build pressure because the A6 has it own oil sump.

 

I failed to mention the following in my post.
It seems as if the AC tech over oiled the system. When I flushed the evaporator a lot of oil came out. Upon inspection, I have oil in both the high and low pressure hoses, the dryer and I now figure I have oil in the condenser.
None of the above will account for where the freon leaked out but I will start the process of removing the compressor, draining it and flushing out the rest of the system.
BTW, when the system was recharged, the compressor, when turned on, was struggling as when a system is over pressurized, skidding on the AC belt until he relieved some of the pressure and it started to work normally.
High pressure reading was around 130-140 psi ?? and the low pressure was around 35-40 psi.
I will be digging into this in the next day or so.
@icsamerica: After I flush the system out, I will pressurize the system and check for leaks. Got to have one somewhere. Are you saying that 40 psi I put at the evaporator was to low to check it for leakage?

 

I too am getting ready to search for leaks on my X-Type and would like to hear more about the compressed air testing. Do you the high pressure or low pressure fitting and is the whole sytem brought up to 120 pounds.

 

40 psi may not be enough. 100 PSI should be attainable by almost any compressor. If you're comfortable with 40 psi go with it. If no leaks turn up then increase the pressure until you find it. R12 systems typically run in the low 200's on the high side and will cool with as little as 150 psi so 120PSI should be more than enough to fine a leak.

I hook up a set of refrigerant gauges to the low and high side and use a rubber tipped air blower to pressure up the system on the center or yellow supply line until I get the system pressurized, then close off the valves and see what happening at the gauges. At this point its quiet, and a gross leak from a cracked line, condenser or fitting can simply be heard hissing. Slow leaks from hose porosity or leaking o-ring joints can be sprayed with soapy water and then look for bubbles.

Frankly Speaking... there aren't many good mechanics left, market forces have hollowed out the industry. The vast majority of really good mechanics are making 6 figures at a high line dealer. As the owner of a 30 year old car with low relative value the only mechanics generally available are going to be mostly clueless or looking to make money fast. Business conditions as they are leave little room for worthy mechanics to give old cars the time they need. From a business perspective... for example it could take 6 hours to find and fix leak, then having to special order a parts that no longer are locally available so the car may have to sit around occupying valuable work space. Then re-diagnose and re-charge the system. Retail this all could cost easily $800 to $1200 or about 1/3 to 1/6 of the value of the car. And when it all goes wrong the mechanic will disown it. That pushes this purely into hobbyist / DIY territory.

 

Doesnt matter, pressure should equalize quickly.

The only down side to compressed air is moisture. I have a drier on my home shop air and I drain my tank often so it's not an issue for me.

Any paint shop will have in-line desiccant driers that can be had for a few bucks, as good insurance. That said I usually replace the drier in the AC system right before I pressurize it for the final time with refrigerant.

Inline Desiccant Dryer/Filter
Most have a clear section that changes color when the desiccant is exhausted.

 

My compressor can build 150 psi at the tank. When using my air tools I can adjust my pressure regulator to 100-120 psi. I also have two inline filters for trapping moisture since I also paint with this system. After I am done flushing the system, I will reassemble same and pressure test the system as per your recommendations. I will then post the results

 

Veeery interesting. to the point that I might seek to charge and activate
the long dormant AC in my Jaguar. It is all connected. New dryer, flushed condensor, etc. O'wise all as it was when the engine blew. AC doing great at the time!!! Oh, old monster jaguar (Harrington) compressor gone... GM unit plumbed in.


My Jeep blows nice and cold. I've recharged it from the can a couple
of times over the years. The R134 included a "stop leak".
Works, so...


Yean, the average tech in these days of high costs, tx, rent, insurance, utilities, advertising, etc has to "take 'em in and move 'em out". Fast, not much time for time eating diagnostics.


Carl

 

@icsamerica: thank you. Your method was absolutely awesome except my leak showed up at 125 psi. The leak is at the backplate where the high and low pressure lines connect.
The plate is attached to the body of the compressor via 4 large nuts and it is leaking at the joint. If I am not mistaken, there is a large o-ring that goes between the backplate and the compressor.
Now that I have found the leak, the question is why didn't i see traces of the dye there?
I have an A6 compressor from my other Series 3 that I may use for the simple reason that it is a straight on replacement for the leaking one.

 

I've had the same thing happen to me with the dye. Glad the air and soapy water method worked for you too!

 

Frankly said: I think the technician killed your compressor when he didn't drain the oil before refilling (and therefor overfilling the system) no fluids should be pushed through the system after the filter / dryer. A compressor actually is very similar to a turbine. Imagine what happens if that turbine get hit by thousands of heavy droplets?

Have a real A/C technician drain the entire system completely of freon and oil and have him fill the prescribed quantities. The R12 that is now in the system would not go to waste, but merely be used again by any modern A/C service machine.

Any good A/C technician would do this gladly, as any excess R12 would be very welcome. The stuff was banned from production years ago, but the amounts available may still be used to fill old systems. R12 is slowly becoming "unobtainium", so the technician would be happy with every ounce he could lay his hands on.

 

I happen to blessed with a great AC guy... very complete and does most of the dealer work in the area... after having various AC "leaks" and bad parts over years and years... the leak finally got big enough.. he always checks ALL car completely with his sophisticated leak tester.

Turn outs the metal had a bubble that was getting larger at the rear connector area where the O ring goes... he filed it smooth and replaced the O ring and then gave me a very good deal on the next charging etc. It is working great now again... everything has been replaced on this car by he and I over the years that pertains to the AC.

He finds all the things the other AC guys miss... plus he stocks most all of the odd stuff and makes his own hoses... so no delays.. my expansion valve was
converted from the odd Jag flare connection on the bottom to moder so I can use a proper R134 rated valve (no experimental adjusting of the screw on the bottom needed now).

I get 29-32F at the side vents depending on the ambient outside temps... plus with the new electronic heater servo valve from Vintage Air, my heater
really works great.

 

Roger, what's this about the electronic heater valve? I'd be interested in one of those.
(';')

 

The Heater Control Valve kit from Vintage Air (old part # was 50507-VUA) comes with a valve that electronically opens and closes the flowing water with a small motor inside. One water hose connects on one end and other end just connects to the water flowing into the heater matrix. Run the wires inside the car, place the small ECU behind a panel, run the rotary pot shaft to the place where your on/off switch is and replace it. There is a power and ground wire to attach, but the instructions and pictures are great.

It has a small ECU and rotary shaft on the potentiometer that is the control for on/off and heat control. The idea was to get rid of the Jaguar vacuum control lines that filled behind my radio...

It is a direct replacement on my car(s) and even uses the stock Jaguar knob.. either S1 or S2/S3 larger knobs. Looks stock on the dash and works flawlessly all the time.

Cost is about $100 USD. Sorry but I did not get a link to the valve on their website... but it is very clearly labeled.

 

Roger - do you have any more detail on the expansion valve mod?

 

Are you interested in how to adapt the flare on the Jag to the new style expansion valve - he used a brand new adapter that is available at AC shops.. I can get the part number when I find the receipt...

How to adjust the screw on the old style valves to properly meter R134?

 

Both!

If it's straightforward to adapt a new expansion valve that's adjustable after installation - or requires no adjustment then that would be my preferred approach but I'm interested in both solutions.

I'd love to have a decently functioning A/C system this Summer in Hotlanta for a change!

 

This is the method I used on the other S1, it worked fine, I found this on the Forum in the archives:

“The expansion valve in the systems that use the A6 compressor can be adjusted to make freezing air from R134a. Because the R134a molecule is 55% the size of the R12 molecule, it requires a smaller orifice. That can be achieved by removing the expansion valve and turning the Allen screw inside the evaporator end, of the valve, in about 2 turns. This furthers restricts the pintle movement, thus effectively reducing orifice size. Normally a correct adjustment, for R12 valve, would have 3 threads showing before the screw. I’ve tried it on several R134a conversions and it works every time. Just be sure the pressures are correct.”

Still looking through large pile of car receipts for the part number of the piece that adapts the expansion valve on the Jag that uses the flare fitting to a screw on type valve. If I cannot find it I will call and get the number and then post it and a picture.

 

Thank you, sir!