Mercedes-Benz Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
81 Posts
Discussion Starter #1
Hey guys,

A/C question. The A/C does not work on the car, it never did since I picked it up. I converted the R12 connectors to R134a. I did a vacuum test on the system and it informed me that there is a leak. I put 1.91 pounds of freon into the system as well as some UV Leak Detection. I turned the system on but it never did blow cold. The compressor was activated but I did not see it dripping water under the car like you normally would see. I also adjusted the temperature setting to all the way hot from all the way cold and the temperature of the air did not change coming out of the vents.

I did a bit more checking. I plugged up pressure gauges to the low and high sides. From there I turned the compressor on and off but the PSI on the gauge never changed. I am thinking the compressor is faulty.

Is my thinking correct or does anyone have any ideas or thoughts as to what my issue could be?

If it is indeed the compressor, how much of a pain is that to replace?

Thanks in advance.
 

·
Registered
95 E320 Cabriolet, 97 S420
Joined
·
260 Posts
There's a compressor relay by the OVP relay behind the battery under the splash cover. Try that.

I also just had to replace my lower AC hose because it was cracked--it's NLA (according to my indy) so he custom-fabricated a new hose. It runs ice cold immediately, I'm amazed. Check that.
 

·
Premium Member
1995 E320 Wagon
Joined
·
77 Posts
If the compressor is turning on and the pressure remain relatively the same then theres a good chance your compressor is shot. Dont forget to replace the a/c drier when replacing the the compressor
 

·
Registered
Joined
·
81 Posts
Discussion Starter #4
There's a compressor relay by the OVP relay behind the battery under the splash cover. Try that.

I also just had to replace my lower AC hose because it was cracked--it's NLA (according to my indy) so he custom-fabricated a new hose. It runs ice cold immediately, I'm amazed. Check that.
I looked under there but I did not check any of the relays there. I might look into that here in a bit. I did find that my HVAC Heater Control Valve is possibly faulty. I am going to look at replacing that and see if that resolves my issues.

If the compressor is turning on and the pressure remain relatively the same then theres a good chance your compressor is shot. Dont forget to replace the a/c drier when replacing the the compressor
I manually checked the compressor by spinning it by hand with the car off. I was able to feel resistance like you would have with a working A/C and it made the typical suction type noise like it was moving freon gas around. I will look further into this once I swap out the Heater Control Valve and see if that makes a difference.
 

·
Premium Member
1995 E320 Wagon
Joined
·
77 Posts
I looked under there but I did not check any of the relays there. I might look into that here in a bit. I did find that my HVAC Heater Control Valve is possibly faulty. I am going to look at replacing that and see if that resolves my issues.



I manually checked the compressor by spinning it by hand with the car off. I was able to feel resistance like you would have with a working A/C and it made the typical suction type noise like it was moving freon gas around. I will look further into this once I swap out the Heater Control Valve and see if that makes a difference.
The heater valve wont do anything if your a/c line isnt getting cold.
 

·
Registered
W124
Joined
·
5,300 Posts
If you have sufficient pressure in the system to allow the compressor to come on, and it stays on, then the KLIMA relay is not the problem. Not building pressure either indicates a bad compressor or a humongous leak.
 
1 - 6 of 6 Posts
Top