1986 300SDL Air conditioning problem
 

I recently bought a compressor from Mercedes shop and had my mechanic install it. After he installed it, it didn't work - he said that the compressor was cycling between "On and Off" and his readings for the coolant indicated high pressure. What could cause this? He said he would eventually find out why this was happening if he was allowed to work on it for another day. Any help or suggestions will be appreciated.

thanks,

Marvin Smith
e-mail: adree@optonline.net

Two possibilities immediately come to mind.

Too much refridgerant, or blocked expansion valve.

Did the system work before you installed the compressor?

That climate unit could be at fault. Also, the SDLs use a speed sensor on the back of the compressor to turn on/off... if it's bad it could be causing your problems.

Also, when the compressor was replaced the dryer was replaced too correct?