KhalilTam

I have w211 m271 engine for about a year now and the ac was working fine and never has a problem but two days ago the AC suddenly stopped blowing cool air ... When tried to turn it on the radiator fan turns on but there is no cooling or anything I have checked the fuses and took it to a dealer who run it through a scan then told me that the compressor had failed.
So would that be possible to fail with any warning signs and what could be happen inside of it .. cus it looks like it turns with the engine even when it's off.
So do I have to but a new one or there's anything else I can check or do .. thanks

Plutoe

welcome to older very expensive MB's repairs--------and yes if he tested it and it failed it failed------or go get a second opinion from harry on the corner

KhalilTam

Actually was wondering which part has gone inside of the compressor

juanmor40

Photo of the compressor front pulley? Likely a clutchless compressor, so they seem to be turning at all times, even if busted.

these compressors use an electronic control valve that could fail, and compressor will not cool at all. Also, if the signal to cool does not make it to the valve, it will not cool either. The valve cannot be sourced from MB, so new compressor unless you want to DIY.

Long road, and learning curve.. quick fix: new compressor and fingers crossed the diagnostic was correct.

IF you decide to pursue further, here are the 3 compressors for the M271 variants of the W211. Notice a little dot on the bottom rear of the compressor, the dot means the control valve includes a DIODE. That is a very important fact you need to know about the previous compressor. All look the same from afar, but they are subtly different.