Compressor is leaking, damaged by overheating? - PeachParts Mercedes-Benz Forum

ah-kay · #1 07-28-2009, 02:47 AM

Went to Las Vegas with coolant overheating and aux fan not working. A week later all the R134a is gone. A/C was working in that week, albeit a little less cold than it used to be. May be in the mind. Now system would not hold vacuum and pressure tested the same and found compressor is leaking.

Is it possible the aux fan not working overheated the compressor and caused it to leak or is it just a coincident. Do not know for sure whether compressor was replaced since 1987.

#2 07-28-2009, 07:32 AM

I would say that if you drove from San Diego to Las Vegas with the coolant overheating and this is the only consequence you should consider yourself miraculously lucky that you made it back home.

The aux fan is for the express purpose of lowering the high side pressure when it is excessive. You say the compressor is leaking, so I can only assume that you mean at the shaft seal. Excessive high side pressure definitely strains the compressor, but should not blow the seal. It might have been worn and ready to turn loose and this situation put it over the edge. This is all speculation.

I can also only speculate regarding your question. Maybe your reason for the question is to determine whether or not to fix the aux fan. It should be fixed. ANYTHING on your car that is not working properly should be fixed.

Matt L · #3 07-28-2009, 10:56 AM

If not the shaft seal, it could be the pressure relief valve. Those don't always reset properly when they pop.

Where is the compressor leaking? Front, rear or side?

ah-kay · #4 07-28-2009, 12:09 PM

Quote:

Originally Posted by Matt L

If not the shaft seal, it could be the pressure relief valve. Those don't always reset properly when they pop.

Where is the compressor leaking? Front, rear or side?

The compressor is a 10P15C. Where is the pressure relief valve? I will try to reset it as a first step but I plan on replacing it.

I did not know the Aux fan was not working all along. R15 was open and I only found it out when I was in LV when the fan was needed most.

I limped home by jumpering the fan to be ON all the time. I must admit I was very lucky as I had NO wire to jumper anything in the desert. I cut some speaker cables and improvised. It probably was the high temp/pressure that was the last straw to cause the seal to leak.

leathermang · #5 07-29-2009, 01:01 PM

Sorry you are having problems this time of the year...
Here is the blowup of that compressor...

http://www.monstermarketplace.com/Automotive/Landing940a1265.html

I do not know if any safety releases are in the compressor or in the MB system elsewhere..I only have 123 books..

ah-kay · #6 07-29-2009, 01:33 PM

Quote:

Originally Posted by leathermang

Sorry you are having problems this time of the year...
Here is the blowup of that compressor...

http://www.monstermarketplace.com/Automotive/Landing940a1265.html

I do not know if any safety releases are in the compressor or in the MB system elsewhere..I only have 123 books..

Thanks for the info. I am thinking about replacing the compressor rather than fixing it. Any suggestions to get a quality re-manufactured unit as they vary a lot?

It is a DD but it is not too bad to drive without A/C in the morning/evening when I go to work. On the W/E, I have other cars with A/C I can use.

rrgrassi · #7 07-29-2009, 02:50 PM

Buy a NEW not remanned compressor. Get the Hodyon (Hancock Industries) one. It does have stepped ports though. Hancock Ind was hire by GM to "reengineer" the R-4, per the Hodyon website. It is what I have on my car and is now in it's 3rd summer season. I am using Freeze-12, which we all know is a 134a and some other type blend.

zeke · #8 07-29-2009, 02:52 PM

Do you have any leaks from the P/S pump or hoses? I am certain that a leaky front seal allowed P/S fluid to drip on the front of my compressor and ultimately ate the front seal. Replaced it last year and also took care of the P/S leaks and so far so good (well except a separate leak in the high pressure hose, but that is another story)

Oracle12345 · #9 07-29-2009, 03:00 PM

In regards to the orginal poster, there is no link between overheating engine and the a/c system doesnt make sense. A more logical answer would the las vegas heat combined with the wear and tear over 20+ year old components.

rrgrassi · #10 07-29-2009, 04:49 PM

The condensor can get quite warm when the aux fan does not work, soaking the radiator with more heat, since the radiator fan does not pull enough air over the condensor and radiator when in stop and go traffic. This can allow for a faster overheat setting.

I do agree that an overheating car will not kill and A/C system

ah-kay · #11 09-03-2009, 12:32 PM

Fixed the AC. It turned out to be the o-ring and might not be the compressor shaft seal. I bought a compressor before I removed the old one, silly me. I think the o-ring was crimped from prior installation as you can see 2 are broken. Do not know how it could happen but it did. The heat from the trip is just the last straw or simply coincidence. I think the crimped o-ring simply gave way. The original compressor probably is still good and I am keeping as a spare as it fit a number of vehicles. I fixed everything for minimal dollars.

Another footnote is that the Klima relay had always been temperamental as it cut off for some reasons. I butchered it up and by-passed everything except the signal from the Climate Control Unit. The signal from the CCU is active low ( 0v to activate compressor ), which surprises me. I put a small relay in and wired the coil to 12v. It has been working good for a week. The only concern I have is that the Klima is only monitoring the CCU button and freon level but not the compressor rpm speed. Will look at the circuit to see whether I can mickey mouse something for it. Here is the pictures of the compressor and the o-rings from the 4 ports.