Interesting a/c issue on 95 E300, original r134 system - PeachParts Mercedes-Benz Forum

engatwork · #1 07-07-2013, 08:53 AM

Just recently went through and put a new compressor/dryer on the listed car. Did the job right but may have overfilled with oil. The issue now is that the belt slippage system drops the compressor out after running a while and the compressor gets hard to turn (working like it is supposed to). I've removed the compressor once and removed some of the oil and it seems to be doing the same thing. When I took the compressor off and spun it by hand I drained the oil and did not have any issue turning it by hand. Can't turn it by hand on the car until after it has sat for awhile. Seems to work ok as long as I am going down the highway too. Drops out at idle. Does this sound like a system that is overfilled with oil? I've got one source that says a little over 4 ounces of oil and another that says 8 ounces total.

compu_85 · #2 07-07-2013, 09:39 AM

What do the pressures do when this happens?

-J

engatwork · #3 07-07-2013, 11:11 AM

I will hook gauges up this afternoon and post later.

engatwork · #4 07-07-2013, 06:57 PM

idling low 45, hi 275

rev it up low side drops to around 30, hi side 310 and it drops out.

Will sit at idle and pull in/drop out with low side swinging up and down during this time as you would expect. High side around 300. Ambient is 82 dF/90% humidity.

I charged by weight - right at 2.09#

Cools fine when it cools.

tia

vstech · #5 07-07-2013, 07:55 PM

310 at 82F ambient sounds like slipping fan clutch/bad aux fan/dirty condenser coil.

engatwork · #6 07-08-2013, 06:02 AM

System was working fine prior to compressor that got changed out locked up. Could too much oil in system cause this?

lorainfurniture · #7 07-08-2013, 07:34 PM

Quote:

Originally Posted by engatwork

System was working fine prior to compressor that got changed out locked up. Could too much oil in system cause this?

I installed a brand new compressor on my 300e and the clutch was not spaced correctly. Check for clutch slipping just to be sure.

In my case it was too close and stayed engaged. Had to re- do the whole thing after it shredded itself.

engatwork · #8 07-08-2013, 07:48 PM

Thanks.

Plans are to pull the compressor drain an ounce of oil and try again. I have gotten where I can have the compressor off in about 20 minutes and that includes recovery time

. I will check clutch clearance when I pull it off.

vstech · #9 07-08-2013, 10:34 PM

20 minutes is not enough time to recover and evacuate the system. AIR in the system will cause these symptoms also.

engatwork · #10 07-09-2013, 06:01 AM

Thanks. I was just saying that I'm getting pretty fast at actually removing/re-installing the compressor on this application (because I've done it so many times). I've been vacuuming it down for approximately 1 hour prior to charging.

engatwork · #11 07-13-2013, 12:05 PM

Removed a little oil, repeated the vacuum and charge procedure and it blows cold now

. Lo pressure 40, hi side 200. I suspect I had too much oil in the system.

engatwork · #12 08-12-2013, 08:51 PM

Condenser fans are not operating as they should. Will troubleshoot over next week or so.

engatwork · #13 08-25-2013, 12:41 PM

Found relay that operates the low speed fan circuit had a blown fuse. Seems that one of the fans is not coming on as it should. Will run if you give it a twist. Compressor operation is kinda interesting to observe with out condenser fans.