Article by: Winston Fong
Article applies to: all E32 and E34 models.
Remove the cover to the AC sight glass and fill valves, located by the passenger side firewall.
Look at the sight glass.
If you see a lot of bubbles and the AC has trouble cooling you’ve probably found your problem.
If you see only a few bubbles going by it’s probably fairly full and not your problem.
If it’s clear your system is either empty or over full.
If you know the system is full you should see at least one bubble go by per second.
If no bubbles at all then your system is overfull.
If you’re familiar with AC pressure gauges you may connect them at the above valve locations and
check for excessive pressures from over charge.
See that the auxiliary fan is working in front of the condenser. It will be on whenever the compressor is engaged.
If the fan does not come on with the compressor the most common problem is a faulty resistor which is located on the frame of the fan.
If the resistor has continuity then you may have another problem with the fan itself, relay, fuse etc which is beyond what I wish to cover here.