3 replies to this topic

[Martynj]

I'm having an issue w/ my 93 245 where, when I run the A/C the engine starts to run hot (about 10 O'Clock on the gauge). The Temp. Comp board is about 6 months old so it shouldn't be that.

My question: should the auxillary fan run the whole time the A/C is on or does it just come on at a certain temp.?

Thanks,
Marty

[bdimag]

not the whole time, but i thought it picked up on pressure...

this is actually happening in my 244 now -- i haven't looked at it -- just putting up with the heat

[Three Fat Tigers]

The coil for the relay that fires the fan is powered only when the compressor is on, but is only grounded via the high pressure switch up under the right front corner of the car, so both have to be in play for the fan to run. If the fan isn't running, it may be a defective pressure switch or relay. I'd check the fan by pulling the connector off the high pressure switch and jumping the terminals together (with the compressor running), fan should turn on.

Should you want to replace the switch, IIRC, it's just screwed on to an schrader valve, so nothing much lost while changing it.

If the cooling issue is not related to the above, it may be dirt build up in the external fins of the radiator or condenser, bad fan clutch or bad thermostat. Try taking the fan shroud loose and back flush water through the fins using an garden hose. Check the clutch by turning the fan by hand after shutting down an hot engine, should be stiff versus how it feels when stone cold. Try another thermostat.

[Martynj]

It was the pressure switch.
Thanks TFT