[W126 Coupe] AC Problem Part 3

[Markus Meyer]

 Tom, Have you ever had a bad compressor replaced, or is the only work done to your system the items you just listed?  Reason I ask is, I had issues a few years back, and after 3 different attempts, it was finally traced down to a bad suction line off the compressor that had a piece of metal stuck in it.  That caused the restriction, which got worse with each new compressor and recharge.  First one last a year, second one a month, third one two days.  I gave up, took it to Satish who figured it out and had the system corrected.  If you look at the papers coming with the BENZ compressors (don't know about other brands) it says right on there - replace suction line too and receiver/dryer.  I know for a fact my local guys didn't do that, so either they can't read, didn't read, or the local compressors don't come with that info. In your case its hard to know.  After they checked that your system had a vacuum, you say you recharged it.  How?  Did you measure the high and low 
pressures to make sure they were correct?  Does the high side get so hot you can't touch it, and the low side so cold it shows condensation on it?  If not, there is a problem right there (like mine).  Just looking in the sight glass may not be enough.  When they evacuated, did they flush the system too?  When mine was done in the end, Satish said it looked like coke coming out at first, they kept running it through until it finally looked more like sprite. Markus--- On Tue 10/11, Tom Oelsner < toelsner at mindspring.com > wrote:From: Tom Oelsner [mailto: toelsner at mindspring.com]To: mbcoupes at mbcoupes.comDate: Tue, 11 Oct 2005 13:12:38 -0700Subject: RE: [W126 Coupe] AC Problem Part 3I charged it. Again, the system has been working fine for a month. This issomething new.-----Original Message-----From: mbcoupes-bounces at mbcoupes.com[mailto:mbcoupes-bounces at mbcoupes.com]On Behalf Ofairedale at sbcglobal.netSent: Tuesday, October 11, 2005 1:10 PMTo: Mercedes Coupes Mailing 
ListsSubject: Re: [W126 Coupe] AC Problem Part 3Did they charge it too? Why not take it back to them with your complaint?John----- Original Message -----From: "Tom Oelsner" To: "Mercedes Coupes Mailing Lists" Sent: Tuesday, October 11, 2005 2:56 PMSubject: RE: [W126 Coupe] AC Problem Part 3> The system was evacuated by a shop and then had the gauge left in place> for> several hours to check for leaks. All clear on that front. The system is> fully charged. How does one go about looking for restrictions in the> lines?> Tom>> -----Original Message-----> From: mbcoupes-bounces at mbcoupes.com> [mailto:mbcoupes-bounces at mbcoupes.com]On Behalf Of> airedale at sbcglobal.net> Sent: Tuesday, October 11, 2005 12:51 PM> To: Mercedes Coupes Mailing Lists> Subject: Re: [W126 Coupe] AC Problem Part 3>>> Did you do part 1 yourself? If so did you evacuate the system to get the> moisture out? If a shop did it take it back to them. To part 3. Is 
there a> restriction to your condenser or evaporator coil, I have seen items pulled> through the return air that restrict air flow. Under charging will cause> the> evaporator to freeze up and impair cooling. The usual air that comes> through> my supply vent in my '91 560SEC on a 90 or so degree day is between 50 and> 60 degrees. I notice the AC systems in the 89 through 91 hold more R12> than> the 86 through 88. I do not know about the models before that.> John> ----- Original Message -----> From: "Tom Oelsner" > To: > Sent: Tuesday, October 11, 2005 1:32 PM> Subject: [W126 Coupe] AC Problem Part 3>>>> ok...here we go again. Just as a reminder;>> Part 1. Get the AC running. Replaced the compressor O rings, replaced>> the>> receiver-drier, new AC belt, no leaks at all and rock solid. Charged the>> system. cold air!>> Part 2. Belt squeal. Belt keeps loosening (stretching?). 
retightened>> twice>> and loose again even though the idler pulley is tight. Any ideas?>> Jonathan, it is a Continental belt.>> Part 3. THE NEW ONE. Had very cold air until about a week ago. Now it>> is>> only really cold if I am going above 75mph or if the outside temp is>> around>> 70F. At lower speeds the air is somewhat cool at best. Engine temp is>> definitely in range with AC on, 85C to 95C(?) and there is still plenty>> of>> refrigerant in the system. Any ideas? Thanks for your thoughts.>>>> Tom Oelsner>>>>>> The MB Coupes Website!>> W126 SEC Mailing List>> Postings remain property of MB Coupes, L.L.C.>> The MB Coupes Website!> W126 SEC Mailing List> Postings remain property of MB Coupes, L.L.C.>>> The MB Coupes Website!> W126 SEC Mailing List> Postings remain property of MB Coupes, L.L.C.The MB Coupes Website!W126 SEC Mailing 
ListPostings remain property of MB Coupes, L.L.C.The MB Coupes Website!W126 SEC Mailing ListPostings remain property of MB Coupes, L.L.C.

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