rivcal4life

After searching and trouble-shooting based on what I read, I think I've hit a wall.

Scroll down for the short version.

I had the A/C charged today with Freeze 12.

When I picked up the car, they told me my aftermarket serpentine belt was crap and that my tensioner needed to be replaced because the adjuster was stripped. They said when the compressor was connected, the belt would smoke, so they disconnected it at the low pressure switch. The also told me my car was leaking "fluid" so I needed a new radiator.

I took the fan shroud apart to properly tighten the tensioner myself and see if it worked, sure enough it was stripped. There was no evidence however that they took off the fan shroud, so I'm beginning to think they stripped the tensioner adjuster by attempting to tighten it without loosening the lock washer.

Then, I reconnected the low pressure switch and the compressor would just click on and off, not fully engaging.

After some reading, I jumped the compressor and the clutch would engage. I revved the engine, and saw what I thought was the smoke they were talking about. I got out to have my brother rev the engine lightly and found that it wasn't smoke at all, it was FREEZE 12 spraying out of the drier. And that "fluid" leak they told me about was actually freon spraying onto my radiator and dripping off. Is it possible that the freon was over-charged and it now just releasing the excess? Does the drier have an overflow valve?

Short Version:

My compressor does not stay on unless jumped. my drier is spraying fluid like crazy, which I think may be due to an over-charged system if it's possible.

Also, my "specialized" Mercedes mechanic stripped my belt tensioner adjuster.

ps2cho

I am not sure about the overflow...but with my A/C on my 260E, the compressor would keep switching on and off....I swapped the Klimate relay with a spare I had and it fixed it. IIRC the correct amount of freon from empty should be about 30oz....so usually about 2.5 cans

Can you figure out how many oz were put in?

Which indy did you take it too? Just interested so I know to avoid this person if I ever need to take either of mine to one.

Real1shepherd

I can't help ya on the A/C question but without a doubt, your mechanic stripped the belt tensioner. 99% of the time, they get stripped from a heavy-handed mechanic at some point, rather than fail themselves.

Kevin

rivcal4life

Ive never adjusted the tensioner, so I have almost no doubt it was them. Im guessing they saw the smoke, and just assumed it was the tensioner.

I have the r12 system (which can run freeze 12 interchangeably) and the capacity is 2.2lbs. Not measured in .oz or cans.

rivcal4life

UPDATE:

After speaking with them again, they said they never bothered to try to adjust the tensioner. The owner said he could tell the rod was stripped just by looking at it, so he did not even turn it.

He has no idea why the drier would spray like that. Apparently there is only one valve on top of the drier that blows when the system is completely over-pressurized, and does not reseal. "When it blows, it blows."

BUUUTTTT In my case, it didn't just empty the system. I was able to get it to go twice.

He also told me that the system can not be overcharged.
What would make this happen? Clogged lines? Messed up condenser? ughghh.

Real1shepherd

If you never touched the belt tensioner yourself, some mechanic in the past did it...play detective and figure it out....maybe you can get a free one if you have good rapport with the mechanic that did it, or at least a free install if you buy the part? Just an idea.....

MB A/C systems are not overly complicated-at least not the part of charging them with Freon. It's pretty basic really and a lot less complicated than a commercial or home A/C system. If they think it's leaking they can use dye to find the leak etc. Most systems, yes, have a blow off valve of some kind to release after too much pressure. The condenser....yeah well, MB decided to put it deep in the bowels of the firewall on the W124...even have to remove the windshield wiper assembly and the fan to get to it, which in and of itself is a pain.

When I was fixing my fan recently, I looked at that condenser and made some sort of prayer to the car gods.

Kevin

rivcal4life

So I think I've decided to grab another tensioner from the junkyard and go from there. I'm going to try and get away with doing just the rod and shock.

Then hopefully I can figure out exactly whats wrong with the A/C.

Real1shepherd

You should be able to tell with the junkyard tensioner if it's stripped/sound or not. Good luck with the A/C...post what the fix is!

Kevin

RedG

Aside from all the other problems it is quite possible to overcharge an A/C system. There would be way too much pressure on both high side and low side lines, and it could potentially raise internal PSI to catastrophic levels (blowing out the weakest components first, like the receiver/drier).

Find a different mechanic. I would start by having the system evacuated and recharged to properly full levels. Once there than you can diagnose for further issues. It is also quite possible that a seal has just failed on the drier as well. Was that ever replaced before? Or have you had a condenser or any other a/c parts replaced in the past WITHOUT the drier and orifice tube being replaced?

rivcal4life

I have not serviced the A/C at all since I've owned the car.

Another update however, before heading out to the junkyard, I was gathering toold when I decided to give the compressor one last chance. This time, it would stay one for a few minutes, even while reving the engine. I was able to drive around the block and the air was blowing cold and hard, but once the engine heated up, the clutch would not stay engaged. This points me towards the klima relay. I could not find the relay, so I am led to believe it is integrated into the MAS.

Can anyone tell me what pins to bridge on the MAS in order to troubleshoot and see if it should be replaced/fixed.