Khanzada6

Hello members,
I happen to have a W220 S320 cdi and recently i encountered a very bizzare problem with its AC. It worked well and seemed to be in good shape more than a month ago but since a few days the AC suddenly stops blowing cold air after running for a few minutes, i give it a rest, reset it and it goes on well again for a few minutes. Ive checked each an everything in detail, scanned the car repeatedly but i was unable to trace the issue. The only appeared errors after reseting the climate control unit are NR:00 and Error 1270. However two of the MB experts i know have suggested to change the compressor but its very expensive and once installed the retailers wouldnt accept a return incase the issue is somewhere else. Id be very grateful for you kind help in framing the possible issues in my car.
Thankyou very much before hand.

tusabes

are you certain it is full of r134 refrigerant ? Low refrigerant level will cause the compressor to shut off to protect itself . That is the most common problem

Astro14

Start with the simpler and cheap: check the refrigerant level.

Don't confuse pulling codes with actual diagnosis...

wallyp

One of the primary principles of diagnosis/troubleshooting is to continual split the probable location of the problem in the affected system in half. In this case, the first quick, easy check will tell you whether the problem is in the refrigeration system (including its controls) or in the main HVAC control system.

When the HVAC air turns hot, leave the engine running, open the hood/bonnet, and feel of the metal HVAC lines on the left fender. One line should be cold, the other should be hot. (You might also want to do this when the system is giving cold air, so you know what the normal conditions of the lines are.)

If they are, the refrigeration system is working. If they are not, the refrigeration system isn't working.

Khanzada6

What should be the exact pressure of the refrigerant.? It falls between 20-30 bars on the guage when the pedal is pressed.

Khanzada6

Ill check the lines right away and additionally i wanted to mention is that it works rather better and longer when i spray water on the front condenser.

wallyp

Do you have full fan speed?

Khanzada6

yes i do