My '05 E320 wagon has never had great AC-had to add refrigerant last summer, it was cooling adequately. This season, it often does not seem to be cooling at all. No difference in temp between high and low side lines, ambient-temp air from vents. All fans are working normally. The one under the hood is really revving! When driven, cooling slowly starts to occur; my wife just reported that it seems fine at freeway speeds. Hitting a bump SEEMS to help or hurt-randomly. Engine temp is always fine-no problem with radiator/condenser fan. Rear vents are not hot-no changeover valve problem likely. Any ideas out there?

 

I was wrong, I thought you drove w210---on the W211 you need someone with the factory diagnostics(DAS Xentry) to recover the AC faults and the actual values. That information is needed to determine solutions to your problem.

 

I don't have any faults showing-where would I find "actual values"? I don't see any stickies directly referring to these phrases or AC problems.

 

There is no way to do that on your E320 without taking it to a shop. The basic two zone climate control on the W211 does not have that functionality.

I believe you've overcharged the system. The fan running at high speed & no cooling at idle/low speeds points to this. Hopefully you
used plain R134a (without generic oil & "leak stop") and haven't created any other issues with the system. This is why it is not
advisable to recharge variable displacement compressors at home, you're working blind!

What you need to do is go get the A/C system evacuated & recharged with the correct amount of refrigerant at a dealer or
independent that specializes in MB ($150-$250?) & go from there.

Let us know how you make out.

 

You may be right about the overcharge, Chris-but the symptom started/got worse this season before I added any R-134 (and that is all I used). Driving it today, I really noticed it cooling after hitting bumps. Going to check for loose/damaged wiring to the compressor first-that's free!