Quick Aircon question

[bish789]

Hi yall.

Can anybody tell me if the engine cooling fan on an 850t5 comes on all the time when the aircon is switched on, or only when the engine gets too hot as you would normally expect i.e. when stood in traffic.

[Wobbly Dave]

The 2 systems might be related.

usually the engine radiator fan works of a thermocouple based on the temp of the water going around the system, i.e. engine block.

A/C works of a compressor that is running off on of the pulleys (via a electromagnetic clutch) driven by the serpentine belt. The cooler for the a/c is sandwiched between the intercooler and the rad.

As such the temp of the A/C cooler could affect the temp of the water in the rad.

Someone tell me if I have got this wrong?

[bish789]

I've just had my aircon sorted out after it not working since buying the beast, and the guy who did it was under the impression that all the time that the aircon is running, the cooling fan should be as well, but I just can't see that being the case.

If you're driving, there is enough air forced through the rad system to keep the engine fairly cool, but when you're stood in traffic, the fan would come in as the engine starts getting hotter.

As the fan is a two speed one, i.e. general cooling when hot, and then oh my god we're really hot cool me down now mode, I would have thought this would cover it.

I don't want to start looking for another fault if it aint there.

[Wobbly Dave]

I don't understand what the problem is?