Ok, I bought an infrared thermometer today and some R12 manifold gauges and did some checking. I am now beginning to think it might be a bad fan clutch. The temperature at the drier switch really struggles to get to 52C so the aux fan doesn't come on much - when it does the fan works fine. The high pressure is between 250-275 psi and low side is around 30 psi, with idle at 1500-2000 rpm (that was with the aux fan running).

While idling with the A/C on, the idle is slowing down a lot and the A/C clutch stops periodically - just for a second or so at a time. If the aux fan does not come on the car may stall. Could this have something to do with the fan clutch, or something else?

Again, if I jump the drier switch and let the fan run all the time the A/C clutch seems fine and the car idles fine.

Ahy thoughts? Thanks,

ryan

__________________
RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE