A/C help with my 2.3-16v
 

Hello,
I am having an A/C cooling problem with my 1986 w201 190e 2.3-16v.
It cools for a while then goes warm. After it sits off for a while it will go cold again. Seems like the compressor is turning off once it has been on for a while.
First a few questions. It has been converted to R134. How many pounds or how much R134 should be put into the system from a vacuumed down system? Also how much oil and what type of oil? I have hear that is takes about 10% less R134 over the R12 original. I am thinking that th system maybe overcharged since freon got added since it was filled. It may have a very slow leak, but it may not have the correct freon charge in it now. I have a set of gauges, a vacuum pump, and access to R134 freon. I just havent worked much on my Mercedes AC systems. I was working fine last season. When it does blow cold it blows decently cold and the volume of air is fine. It needs the fan motor replaced, have a new one but not done yet, due to a squeal and it doesnt always turn at the lower speeds until I move it to max fan speed to get it moving.
Christopher

You should go ahead and replace your blower motor, since it does stick at low speeds... If you don't you will be replacing the speed control, too.

I'd get the gauges on it and see what the system is doing.

Could be low on charge?
Could be a switch problem (low/high pressure)
Could be evap temp sensor causing the climate control unit to kick off the compressor?