Let's try this again. Help!! A/C problem - PeachParts Mercedes-Benz Forum

85 500sel · #1 08-09-2008, 06:28 PM

I need to reiterate my ac problem. My a/c will only blow warm air. I took it to my indy and they topped it with freon. It got cool, but later on in the day it got warm and has been warm every since. They checked it for leaks and they found none. Before they charged it the clutch would not engage. After they charged it the clutch engaged. Now the clutch does not engage. If there is no leak where is the freon going?. Also, the auto fan switch will not engage. When I press it the spring will not hold. I have to run it on low or high fan. I read the diy links about the monovalve and it does not seem to apply to my problem. What could be some other culprits? Could it be the compressor? I need to be able to tell my indy some things to try. I hate to pay the big bucks for a compressor if I don't need to. The car is a 1985 500 SEL. Please advise. Thanks in advance.

compress ignite · #2 08-10-2008, 12:54 AM

it's an '85 ?
The Monovalve rebuild kit is cheap.

crashone · #3 08-10-2008, 08:34 AM

You will be amazed at what a mono valve rebuild will do for your car. 5 minutes to fix, years to enjoy.....

85 500sel · #4 08-10-2008, 08:59 AM

thanks a lot. I will try the monovalve. Crashbone where are you in reference to Raleigh. I'm only about a couple hrs. away in northeastern N.C.. I will be in Raleigh in a couple of weeks. Thanks again.

slk230red · #5 08-10-2008, 09:09 AM

Quote:

Originally Posted by 85 500sel

I need to reiterate my ac problem. My a/c will only blow warm air. I took it to my indy and they topped it with freon. It got cool, but later on in the day it got warm and has been warm every since. They checked it for leaks and they found none. Before they charged it the clutch would not engage. After they charged it the clutch engaged. Now the clutch does not engage. If there is no leak where is the freon going?. Also, the auto fan switch will not engage. When I press it the spring will not hold. I have to run it on low or high fan. I read the diy links about the monovalve and it does not seem to apply to my problem. What could be some other culprits? Could it be the compressor? I need to be able to tell my indy some things to try. I hate to pay the big bucks for a compressor if I don't need to. The car is a 1985 500 SEL. Please advise. Thanks in advance.

If the clutch is not engaging, then it sounds like you have a leak. The sensor on the drier/receiver is doing what it is designed to do...turn off compressor when freon is low.

Have you tried jumping the connectors at the drier to engage the compressor clutch momentarily to observe the sight glass on the drier and also to feel the suction side hose to verify if the system is cooling?

My guess is that you have a leak, which is what your indy should have checked for after charging the system.

POS · #6 08-10-2008, 09:21 AM

You need an indy with a gauge set and a sniffer. Sounds like you have a leak to me too, regardless of what your garage said.

85 500sel · #7 08-10-2008, 09:30 AM

O.K. I will get a second opinion to check for a leak. By the way, when the a/c was fully charged it did not really get cold it just got cool. Should a 85' get cold?. My wife's 300e is a 93' and it gets freezing cold. If there is a leak then what? I will do whatever it takes to get my a/c cold. I just don't want to keep wasting money. Thanks for the advice.

stevebfl · #8 08-10-2008, 09:36 AM

If you put in refrigerant and later don't have it you either have a leak or a thief. If you have to bring service suggestions to your indy you need a new indy.

There could be other reasons why your compressor isn't engaged but the monovalve is NOT one of them. Fix your obvious issue before throwing parts at it.