Another 300SD Om617 A/C Question. - PeachParts Mercedes-Benz Forum

dinman · #1 09-28-2019, 03:39 PM

Hey guys

So I have this super, super minty 1983 300sd that I picked up. It was lightly wrecked in the front, and stored for months. Two owner, extensive Service records.

Car is unbelievably original. 150k miles, cruise works, other than my current a/c issue and the tach jumping around, I can't find a single issue. Paint is good, no wood cracks, blue leather shielded by sheepskins it's entire life, etc

So when I bought it (May 2019), the a/c was blowing ice cold and was making no strange noises. I went out of town for work from May until now, and now here are my symptoms

1.) Blows cold still
2.) Can see clutch engaging
3.) High/low side pressures are normal
4.) Aux fan does NOT kick on
5.) When under rev, it sounds good, when coming down to idle after running the a/c for a minute or so, the compressor "seems" to lock up intermittently, so the belt screeches.
6.) Belt is pretty loose IMO, I need to tighten it but I just had surgery and can't do anything like that for a good while

Is my compressor going bad? I sure don't mind replacing it, but would rather not if it could potentially be something more simple

Thanks!

Sugar Bear · #2 09-28-2019, 04:14 PM

Could be a loose belt,
overcharged AC system,
moisture in the system causing icing and/or
the compressor going bad. If the compressor is failing it is better to change it early to lesen the debris put into the system.

Probably should start with a good tight belt and gauges on the A/C to check the high side pressure when the belt slips.

Good luck with the recent surgery and the car!!!

dinman · #3 09-29-2019, 01:04 PM

Quote:

Originally Posted by Sugar Bear

Could be a loose belt,
overcharged AC system,
moisture in the system causing icing and/or
the compressor going bad. If the compressor is failing it is better to change it early to lesen the debris put into the system.

Probably should start with a good tight belt and gauges on the A/C to check the high side pressure when the belt slips.

Good luck with the recent surgery and the car!!!

Thank you!! Sucks to want to work on the car but being limited by surgery

I will check that out. Didn't even think to look at the gauges when it started locking up.