[s-cars] After Run Fan and Coolant Pump on at Lower Temperature

[Sean Douglas]

I figured out a way to make the after-run fan (and coolant pump) come on
more frequently. I purchased a temperature switch from a 1990 90q20v
(p/n 034 919 369 A) for $25 which measures underhood temperature (not
coolant temp) and is set to turn on at 85 celcius and off at 80 celcius.
The switch is threaded with a 10 mm thread and I picked up a used
mounting bracket from a 1990-1992 VW Passat 16V and mounted it along
with the switch on the valve cover using the rear allen bolt on the
passenger side. I extended the wires that feed the stock switch and ran
it to the new switch.

Now the after-run fan and pump comes on about 80% of the time. I tried
mounting the switch on the driver's side, but it did not get hot enough
to trigger the switch. Since the switch is just above the downpipe, it
will see the highest temperature.

FYI, the stock switch doesn't come on until the coolant gets to 110
celcius which takes quite a lot.

Sean

Sean Douglas
1997 Audi S6//RS2-spec
1990 Audi 90 quattro 20v