Hey there new to the forum im Vr4junkie over on galantvr4.org i'm having a problem with my ac compressor for some reason it smokes every time I have it on and engine power goes down not sure whats wrong. But smoke goes away on the freeway when cruising about 70mph just stop and go traffic were it smokes the most but when AC is off car runs nice and strong.

It has a new air compressor and expansion valve and heater core is disconnected.
Oh yea its a 84 300sd ill see if ill post a pic
Any help or suggestions is greatly appreciated thanks.

 

"ac compressor for some reason it smokes" Does this mean that the AC Compressor itself is smoking?
Meaning that the AC Compressor Belts are not smoking and the Car is not smoking out of the Tail Pipe.

 

No smoke comes out the exhaust should of specified better .

ok driving normal with out AC car drives fine picks up speed decently.

AC on car seems a little sluggish at a dead stop like if it was struggling but after 25mph you can see a light hint of black smoke every now and then while it shifts also power band doesn't feel the same.


Is this the right section to post up 300sd questions?? New to this forum

 

This is the part of the Forum for Diesels. Some Forums have them divided by Chassis some have a Diesel Talk section and there may or may not be a Vintage section for older Cars.

Apparently the AC system was recently worked on. It could be something in the System causing an abnormal extra Load on the Compressor.
Don't know much about AC but I have read that if the Reciever/Dryer is exposed to Air it corrodes inside and can block the Flow. But, I do not even know if the Mercedes system has that part.

Then there is Engine issues like the need for a Valve adjustment, Valve Timing (Timing Chain Stretch), Fuel Injection Pump Timing and the Condition of the Injectors.
As well as Engine Compression (How many Miles?). That can cause smoke.

I also recently read a thread on another Forum where a Member was have an issue when the AC was on; in this case hunting/pulsating Engine Speed and one of the Posters suggested it was an internal adjustment (there is an internal idle speed adjustment as well as an external one).
I am not sure of what the Poster is describing but I know from Trade School there is something called Governor Droop. It has to do with how fast the Governor responds to the load. If it does not respond fast enough you get that hunting and fluctuation of rpm.

Also what is your normal Idle speed set at? What is the Idle speed when the AC is on.