Dear Forum,

Can the A/C Compressor O-Rings be renewed in situ, or must the Compressor be removed, please?

 

It can be done in situ. It looks like the 3.5 is the same procedure as the 4.2, which I did just yesterday because the o-rings I ordered and installed when I replaced my compressor were not the correct size for my car. Assuming you have a left hand drive car, as I do, this is how I did it:

1. Remove the air filter box, intake hose and engine cover
2. Jack up the left front and place on a jack stand. Remove left front wheel
3. Place a bottle jack beneath the oil pan, with a piece of lumber between the jack and the pan to distribute the load. Raise the jack to just make contact with the pan, but do not lift the engine yet
4. 
   
5. Locate the left hand side engine mount nut. It is located in a tubular cavity in the subframe, just in front of the steering rack and pinion assembly
6. Remove the lower engine mount nut on the bottom of the rubber isolator
7. Raise the engine until it begins to be resist, about 7 cm
8. Now you will have access to both a/c line bolts from above
9. With a very long extension, remove the a/c return line bolt (the more reward line coming from the cabin, 10 mm, m8)
10. Lower the engine back down. Make sure the stud on the isolator is fully seated
11. Now you have access to the return line from the bottom
12. 
    Red circled area is where you will access the return line. In this picture the engine is raised so you can't see the return line.
    
13. Lift the return line up from the compressor. This might be a little difficult, but it should lift out. Now gently pull the return line toward you to have access to the o-ring. I suggest oiling the old o-ring before removal to help it release more easily.
14. Lubricate the new o-ring with the correct a/c oil and fit to the return line
15. Reinstall return line and raise the engine back up
16. Reinstall the return line bolt and tighten to 20 nm
17. Now remove the supply line bolt (10mm, m6)
18. Pull straight up on the supply line and it should release.
19. You can lift the supply line up and all of the way out for easy access. Lubricate and remove the old o-ring. Lubricate and install new o-ring
20. Reinstall the supply line and torque the bolt to 20 nm (not sure why an m6 and an m8 bolt have the same torque values)
21. Lower engine, again making sure the isolator stud is fully seated. Tighten nut securely.
22. Reinstall wheel and lower car
23. Reinstall engine cover, intake hose and air filter box
24. Torque the wheel lug nuts

That's pretty much it. It took me about an hour to do the compressor and condenser o-rings, but I was aided by the recent experience of replacing the compressor. I would suggest applying some nickel anti seize to the threads of the ac line bolts. Good luck!
-j

 

I just checked and found that my ac system held vacuum for 24 hours, so looking good.

 

Thank you Jacuar for your very detailed response!

 

You are welcome and I hope it helps!

 

It certainly does!

A couple of quick questions you may be able to help me with:

My Compressor was working okay (albeit at a lower system pressure than optimal) up to a couple of weeks ago; Whenever I tried re-pressurising the system it had leaked (through the O-Rings) back to this 'okay' level and then stayed there. Now it has failed alltogether and is covered in (presumably) Refrigerant Oil and there is little pressure left in the system. What caused you to replace your Compressor...I (obviously) don't want to replace the O rings only to discover that my Compressor itself has failed. Any clues as to what symptoms show indicating total failure would be very welcome, please?

Do you know the size of the O-Rings please? I have the following kit:




O-Ring Kit

 

These compressors are a bit unusual in that they do not have clutches. They are always enabled and the climate control computer determines the proportion of duty cycle that is to be used from 2 - 100%. In the event of the compressor becoming seized, the pulley has a destructive failsafe in which it will become divorced from the compressor shaft so the accessory drive belt will be protected. This converts the pulley into an idler and the compressor will no longer function. My car had been sitting for at least six months and the compressor had seized internally.

Here is my old compressor. The square-ish part attached above the pulley is the drive plate that is fixed to the compressor shaft.




Here is a photo with the drive plate removed. You can see there is a blue epoxy that is bonded to the pulley. It is normally also bonded to the drive plate, but will break off if the force needed to rotate the compressor shaft exceeds the adhesion limits of the epoxy. Actually, in my case it was the adhesion limits of the paint on the drive plate that the epoxy was attached to.

So this is the reason I needed to replace mine. There wasn't any other visible issues with it other than being seized. When I removed it I didn't find any oil in it, which I am very curious about, since there is no record of the A/C system being serviced.

The o-ring sizes I used differed from the sizes posted by other members on this forum, so please keep that in mind. The old o-rings in my car measured 24 x 2.5 mm on the return line and a 10 x 2.5 mm on the supply line. I installed the same sizes and so far no leaks and A/C is operating normally. You have something close to the 10 x 2.5mm (10.77 x 2.62), but I don't see anything close to the 24 mm o-ring. What you really want is HNBR (Highly Saturated Nitrile Butadiene Rubber) due to its excellent resistance to R-134a refrigerants. These are normally green to distinguish them from other types of o-ring material. The vendor I ordered mine from did not have HNBR in these sizes so I ordered EPDM (Ethylenepropylene-diene rubber), hopefully these will hold up, otherwise I will have to find an alternative.

I suggest replacing the dryer desiccant bag located on the right-hand side (when facing the engine) of the condenser in a tube. The desiccant is necessary to remove moisture from the air, preventing internal corrosion in the system.

I am not sure what has happened to your compressor. I have not opened my old compressor yet, but will do so soon when I have some time. I am wondering if the case has a large o-ring or seal that has failed on yours. Otherwise, I can see a complete failure of either the supply or return line o-ring leading to what you have observed.

Anyway, it's not much more of a bother if you have to replace your compressor since it is only few steps away from replacing the o-rings. The only additional things you will have to do is remove the accessory drive belt from the compressor, completely remove the engine mount, drop and suspend the rack and pinion assembly and disconnect the electrical connector. The best way to remove the engine mount is to use a very short wrench to unfasten the upper nut on the isolator, which will then give you easy access to the front engine mount bolts. You can find the instructions in the service manual available in this forum.

Good luck and I am looking forward to your updates.

 

Again Jacuar, thank you for your very helpful reply.

Is the dryer desiccant bag integral with the Radiator, please? (I ask, because I recently replaced my Radiator with new)?

It may take me a little time to source and receive the correct O-Rings, but as soon as I do I will start and update my post!

 

Hi ES Ray
I see that you have recently replaced your rad and I would like to know

where you sourced the new part please and did you do the job yourself.

Thanks

 

Hello Meirion1,

It was part number C2C36506A . I bought it locally (Sharjah, Emirate next door). Cost AED 600 delivered by courier ( around AUD 220). Probably Chinese! Looked okay, though and seems okay (so far)!!

 

Jacuar, Please ignore my comment above...I am just being stupid...Now I stop and think a little more clearly...The A/C Condenser is the small 'Radiator' in front of that for the Cooling System!

Please could you send me a link to where you bought your O-Rings and Desiccant? I am struggling to source them here in Dubai!!

 

I bought the o-rings from the o-ring store:
https://www.theoringstore.com/store/...ndex&cPath=368

and the desiccant bag was from pitstopauto:
https://www.pitstopauto.com/Catalog/...&vepid=1006018

Hopefully they will ship to you. Good luck!

 

If you can't find a source for the desiccant bag, you can get by with your existing one as long as the bag itself is still in serviceable condition (not brittle or damaged). The desiccant bag is filled with silica gel that can be reactivated, at least to a reusable degree. Heat an oven to ~ 90 degrees C and bake the bag for about 20 minutes and then store in an airtight container. Wait to reinstall it just prior to applying vacuum to the A/C system. The longer it is exposed to the atmosphere the less effective it will be.

I had to do this before in our Landcruiser, when we lived in Uganda when I couldn't source a replacement. It worked very well!

 

Hello Meirion1,
Just realised I only partly answered your questions!
Yes, I did the job myself.
Used a combination of this (rather annoying) video and the Workshop Manual?


Obviously took longer than I expected...But when doesn't it?

 

Many thanks for the video

 

I do feel for the young chap in the video who found a crack in the rad

after fitting it.
I have now sourced a new rad for the Jag (Mahle ) made in Germany hopefully

after a lot of searching and on their website they do warn about many poor quality

rads on the market.

 

Jacuar,
Is the 24 x 2.5 mm & 10 x 2.5 mm inside diameter or outside, please?

 

It is the inside diameter. I just rechecked and the "10 mm" ID o-rings actually measure out to 11 mm. When I installed the new 10 mm o-rings, all seemed fine. There was a proper amount of drag between the orifice and the pipe/o-ring. If I were to do it over again, I would order both the 10 and 11 mm and see which fit better.

 

I would also replace the condenser o-rings since they are the same 10 - 11 mm size and takes only a few minutes. You're going to have to order a minimum quantity anyway.

 

Hello Jacuar,

Update: I am still trying to source the O Rings; All of the HNBR sets I can find only go up to 17. something mm?
It is relatively cool here at this time of the year (25/26 C) and my Jag is a daily driver, so I do not want to take it off the road until I have the correct parts to get my A/C working?
However, I am unsure whether continuing to spin the Compressor with low or no refrigerant and lowered oil (oil has leaked all over the compressor) could damage it? I have switched the Climate Control off, but with no clutch, I assume this makes no difference?
What do you think...Sooner rather than later? Obviously I would rather not have to replace the Compressor? Or am I being a typical paranoid Jaguar owner?