95 XJS AJ16; does not cool well at idle, does fine in motion. Is the aux fan supposed to run when the AC is on? Mine does not, only when the engine temp moves above mid normal. Then the AC seems to cool fine at idle. Is this the way the system is set up, or something amiss? Thanks for any info.

 

The aux fan is activated by a thermostat. Not sure what temp activates it, but I'm sure it's somewhere in the 200F range.

Do a search for aux fan mod and you should find the, rather simple, instructions on modifying the aux fan to come on with the A/C or the thermostat, instead of just the thermostat.

You'll need some wire and a relay.

 

Yes perfectly normal, (but not necessarily optimal ) the fan is only controlled by the thermal switch in the radiator and is completely independent of the A/C.

It is designed to switch on at 96C and off at 91C. Because of it's location about 1/3 of the way from the top of the radiator, coolant temps exiting the thermostat are about 100-103C (~212-218F ) before the fan switches on, this will show as about halfway between N and H on the gauge, however this is still in the 'normal' range as far as Jaguar are concerned. This pic shows my gauge just before my fan comes on.



Cheers,

Allan