Oil cooler fan manual over ride switch & lower temp thermostat choice

[alf]

My oil temp hit an all time high (9 o'clock or about 230F) sitting on the tarmac waiting for my turn at the Skills day this weekend.

I read some old posts about putting in a manual over ride for the oil cooler fan and switching over to a lower temp (90C or 99C) thermostat to get the fan started sooner.

Anyone have a detailed "how to" on putting in an over ride switch?

Which thermostat would work best? 90C/194F or 99C/210F?

thanks
alf

[widebody911]

I have a Hayden unit that kicks in @ 180-190 or so. $15 at the FLAPS

[emcon5]

Originally posted by alf
Anyone have a detailed "how to" on putting in an over ride switch?

There really isn't much to it, there is only one wire going to the factory fan thermoswitch, it completes the circuit by grounding the wire, energizing the relay and turning on the fan.

All you need to do is tap into that wire (or spit off it at the thermoswitch) and run it to a switch on the dash. Connect the other side of the switch to a good ground under the dash.

Tom

[Rouxzy]

I'm with widebody. Change the thermoswitch for the fan to kick on earlier. I just installed a carrera oil cooler and thought about putting in an over ride switch but figured that the fan will kick on at about 190 so why bother to put it in. Go with a new thermoswitch. You can get it here at Pelican for $18.50.
Tom

[kepperly]

Note if you are going with the pelican lower temp switch,
it is a part for BMW radiator fans and has two terminals
instead of one, one connects from the relay and the other just goes to a good ground.

Keith

[alf]

Pelican has 2 temp switches. One for 195F and the other 210F, i would imagine that the 210 would make more sense assuming the ideal operating temp is between 180 and 200F?

How would i hook up a manual switch with the BMW part?

thanks
alf

[emcon5]

Originally posted by Rouxzy
but figured that the fan will kick on at about 190 so why bother to put it in. Go with a new thermoswitch.

I had the same thought. I ended up adding the switch when the thermostat quit working (it stuck on, actually). I don't know if it was the switch or the wiring, because I haven't taken it apart yet. It was easier to add the switch than take all the crap out of the wheel well to get to the thermoswitch, and I knew which wire I neded to tap into.

Originally posted by alf
How would i hook up a manual switch with the BMW part?

The exact same way. The switch opperates the same way, just the Pelican/BMW version is wired to ground rather than grounded through the cooler.

Tom

[kepperly]

find the one wire that connects to the oil cooler switch, with the ignition in the run position touch that wire to ground and the
fan motor should start running. follow the wire back cut it in two,
put both of the wires on one terminal of a toggle switch and on the other terminal run a wire to ground. that way if you forget to turn on the switch the oil temp switch will stll turn on the fan.

Keith