Hi there!

On my son's 05 S40 the a/c suddenly turns off. The whole system is brand new (compressor, condenser, dryer, radiator... even a pipe!) then there is no leaks, was working well but recently behaves bad. Sometimes turns on sometimes don't and when is working (which is good and cold) suddenly turns off.

I bring it to the shop and the technician doesn't found anything wrong... in fact works pretty good by 3 days!!! We tough some false contact in the cable at the compressor and after the test was ok. Today after I was driving for a couple miles turns off again!

I don't know what else check... relay, fuse, switch... any ideas?

 

You have to determine whether it is electrical related or mechanical related. I will go ahead and assume that you have no leaks because it comes on and works sometimes.

The most common problem that I have seen on Volvo cars of this age is that the air gap on the compressor clutch is too large and can't engage when the compressor is warm.

 

Tony1963 is right - that's a really common problem, especially with a high-mileage vehicle that's seen lots of A/C use. You can check this by looking to see if the compressor clutch is engaged when the A/C stops working. If it's not engaged, and a light tap on the face of the clutch will cause it to engage (be careful!!!) then you've found the problem.

There are some no-$$$ fixes for this problem, or you can rebuild the clutch, or replace it. I used some gardening wire to shim up my V70's compressor clutch and it worked as long as I drove the car after that (around a year of Arizona A/C duty).

 

Yes, that will work but I prefer to remove the compressor and remove the shim. I know that it calls for recovering the AC charge, removing the radiator fan for clearance and probably other clearance issues on the S40, but it becomes a repair for the remaining life of the vehicle.

While everything is apart, I generally replace the orifice tube and accumulator assembly.

You will have to make the tool to pull off the face of the clutch though. I made one from an old rear brake pad and followed a diagram that someone showed long ago. It works.

 

Clearance on my V70 was horrible, and removing the compressor would have been a gold-plated bear. It took me 15-20 minutes to shim the clutch (with some pretty humorous-looking methodology to reach the clutch) and my kludgy fix seemed to work just fine. I'm never one for tearing apart a system that doesn't absolutely have to be. All the shimming wire did was hold the face of the clutch a couple mm closer to the electromagnet, which allowed it to reliably engage, so as odd as it might look, it works as well as a new clutch, at least until the clutch itself burns out (which I'm guessing will never happen).

But I get the desire to "do it right"... but in my case, that would have meant hours of cramped wrenching in triple digit temperatures. ;-)

FYI, the post I made on the subject is here: https://volvoforums.com/forum/2001-2...-option-78578/

 

I've had maybe 1/2 dozen of these cars over the years have this issue and the first couple I simply installed a reman compressor. When I realized the core issue, I guess I did what I used to do which was remove the compressor and reinstall after removing the shim.

As a dealer, I might not always pursue the easiest repair but I wouldn't want to explain to someone how I did the other repair. Albeit that it works, just not my thing. I do understand your story.

 

Tony, if you're a dealer, there's no way you could be doing the fix I did (at least not unless you had a very compliant, understanding customer). Doing it "right" is your only option, while I am free to pursue the path of least resistance, since I can't sue myself. ;-)

 

Rereading the original post, it was noted that the compressor was replaced which should rule out the clutch gap issue. Since it's intermittent, the tech may have to guess. One thing I'd look into is electrical connections to the compressor as well as the high and low pressure sensors. If you catch a failure, then you can try jumpering the pressure sensors to see if it resolves.

 

Recent laws have changed to allow a ham sandwich to be sued. You cannot, however, name the individual components in the suit. You can't list the ham, bread, mustard, etc individually, you have to name the sandwich.

Volvo Owner vs Ham Sandwich

 

If it's a reman and the clutch passed inspection cold then they will reuse it.

I too think it needs the deshimming procedure. On my 2005 it took 20 minutes as you do not need to remove the compressor. The clutch is easily accessible through the wheel well.

 

Yes, they could have used the original clutch if it tested correctly (which it will even with a large air gap).

You're lucky that the compressor is right out there on your model. You will need to fabricate a pulling device to get the outer piece off. There is also a bolt in the center that needs to come out.

 

Wow... that photo brought a tear to my eye. On my V70, there wasn't nearly enough room to get my hand between the face of the clutch and the metal fender. It looks like fiddling with the A/C clutch on the S40 / V50 would be downright trivial.

 

There are other tricks like removing the motor mount to get a few more inches up or down. Similar to when you are changing the timing belt and need to access the crank pulley and water pump.

And I didn't need a clutch puller. Just removed the 10mm bolt and the clutch came off neatly. Watch for the 3 shims to fall out. Luckily mine remained with the clutch to be removed with a small pick.