a/c should work, but... - PeachParts Mercedes-Benz Forum

connerm · #1 07-21-2011, 07:16 PM

95 e300d, 269,000. Holds vacuum for an hour easily. After owning it for 8 years, a/c stopped a month or so ago because it was a little low on 134. No aux fan, no compressor, nothing. Guy put some 134 in and away I went. Today, took my lovely wife on a 2.5 hour hell ride from WDC to Charlottesville to pick up my daughter with NO a/c. Pulled into a local carquest and the guy said he'd have a look. He hooked up his machinery to the low side valve (it wasn't the fitting near the fender not the one down by the radiator. He said before I started it, pressure was 120 or 130 and when I started it, pressure was 31 or so. Compressor was cycling, Aux fan was spinning, but no cold air. I checked all of the fuses and even replaced the water valve fuse. He thought it might be the water valve but declined to speculate further because he was unfamiliar with the alien being.

I replaced the water valve in 2008 with a new one from MB. I replaced the CCU a couple of months ago with a rebuilt (rebuilt from Phil). Also in the spring, I replaced the Klima relay with a factory oem unit. This is starting to sound like a gremlin to me. Any thoughts? (my girls were not happy) Temp on my car read 104. Other than that, car ran fine, coolant temp stayed mostly below 110. Any help is appreciated.

vstech · #2 07-21-2011, 07:27 PM

"holds vacuum for 8 hours easily" not a sign of a leak free mobile system...

31 sounds low, but not much, what did the air in the cabin feel like? HOT, hot, warm, outside temp... details.

with the "compressor cycling normally", what temp was the low side line?

connerm · #3 07-21-2011, 07:34 PM

Air inside when the a/c was on - wheel turned to solid blue, felt not cool, but definitely not hot. I tried turning it off completely, pressing all of the buttons, all fan speeds. I even disconnected the battery for 5 minutes and tried everything again. Outside air temp was between 99-104. Plenty of 60 mph driving. The guy couldn't fit his gauge on the fitting down by the compressor - pulley was in the way, but he hooked to the upper fitting. This is where he said he got the 31 reading. When I had a little 134 added a month ago, guy said he added some dye so he could see leaks.

engatwork · #4 07-21-2011, 07:36 PM

See if you can feel the hot water lines near the little pump/motor near the battery. Are the ones that feed the heater core hot? May be the pump/motor assembly needs to be checked out.

connerm · #5 07-21-2011, 07:41 PM

Lines going from water valve to heater core are warmish, not hot. Lines into water valve are HOT.

vstech · #6 07-21-2011, 07:42 PM

I'm not familiar with the 95 a/c system and fitting locations... I find it hard to believe there are two low pressure fittings on it. is 31 a pressure reading or temp reading?

vstech · #7 07-21-2011, 07:45 PM

it could be a "podectomy" issue, or a refrigerant issue.
the compressor should not "cycle" it's also possible you have the classic evaporator failure issue. I'd take it to another shop, and have them test it properly.

connerm · #8 07-21-2011, 07:49 PM

Quote:

Originally Posted by vstech

I'm not familiar with the 95 a/c system and fitting locations... I find it hard to believe there are two low pressure fittings on it. is 31 a pressure reading or temp reading?

Not sure John. I'm in the deep end now. Gotta have that a/c so I'll take it to the dealer tomorrow. I'll report back...hopefully not with bad expensive news.

Something is telling me that its that damn climate control unit. I had 3 of them before I bought the reman unit. I just don't trust them.

engatwork · #9 07-21-2011, 07:59 PM

The low side fitting should be out in front of the brake master cylinder 12 to 18". The one near the a/c compressor is the hi pressure side.

connerm · #10 07-21-2011, 08:02 PM

The carquest guy could only get connected to the Low side. Number when engine and a/c ON was 31. I assume it was psi.

connerm · #11 07-22-2011, 04:41 PM

Dealer found traces of dye and determined its leaking at the evaporator. Dealer wants $4200 for the job. Yeah, right. Now what?

leathermang · #12 07-22-2011, 05:17 PM

' AT the evaporator "
or " THE Evaporator"
is leaking ?

vstech · #13 07-22-2011, 06:30 PM

evaporator...
http://www.peachparts.com/search.htm?cx=015238323195528004774%3A_wneywo5nvm&cof=FORID%3A9&q=124+evaporator+&sa=Search&siteurl=www.peachparts.com%2Fshopforum%2Fforumdisplay.php%3Fs%3D%26daysprune%3D%26f%3D15#1075

piccolovic · #14 07-22-2011, 06:50 PM

Get the estimate from the stealership, itemizing what will be replaced and what labor needs to be done to get it working. Then get a local to do it after you order the parts through here or local supplier that will be much cheaper than the stealership's prices . . . or of course, do it yourself.

connerm · #15 07-22-2011, 06:58 PM

Quote:

Originally Posted by leathermang

' AT the evaporator "
or " THE Evaporator"
is leaking ?

Tech didn't indicate at evap or the evap. I told him to look for dye and he found it. That's when the service guy called with bad news. They don't want to do the job any more than I do.

Options: find someone to do it for less...gonna have to be a lot less; inject some sealer and hope for the barr's leak best; do it myself.

In the last few years I've done oil cooler lines, engine mounts, upper control arm, wheel bearings, vac pump rebuild, master cylinder replace, window regulator, brake hose replace, and rear axles on my 85 td.

On my 95 i've done engine mounts, water pump, water valve, fan clutch, master switch, trans cooler lines, glow plugs, power steering pump, window regulator, fuel tank replace, coolant flush, brake hose replace.

This 95 is a great car and I don't want to get rid of it, but I want the a/c working. I think I'm just gonna do it myself.

****ty news on Friday at 4:30 for sure.