Overide Manual Switch For Thermo Fan

[blktoy35]

my ke35 4age small port conversion has a thermo fan set up, ive noticed my fan only kicks in when my (cheap may not be to accurate) aftermarket temp gauge reads around 97 to 100 degrees.....now it only reaches this temp when idle in traffic, i want to have an in cabin switch which allows me to turn fan on earlier but will still allow the thermo to come on when it needs to as it does now....... what wires do i tap into to allow a switch in cabin??? :dance:

Edited May 25, 2009 by blktoy35

[Hiro Protagonist]

my ke35 4age small port conversion has a thermo fan set up, ive noticed my fan only kicks in when my (cheap may not be to accurate) aftermarket temp gauge reads around 97 to 100 degrees.....now it only reaches this temp when idle in traffic, i want to have an in cabin switch which allows me to turn fan on earlier but will still allow the thermo to come on when it needs to as it does now....... what wires do i tap into to allow a switch in cabin??? :dance:

 

Out of curiousity, why? If the thermo-switch for the fan is operating properly and switching at the correct temperature, then there should be no need for an over-ride switch. Generally when travelling on the open road a thermofan won't be activated since there is enough airflow over the radiator for it to not be needed - it's only when the car is slow-moving or stationary and there is next to no natural airflow that the fan kicks in to boost the flow.

[blktoy35]

yeh it seems to work its just for peace of mind i would imagine when its engaging its at the temp required but my gauge shows between 95 and 100 degrees, when moving its fine, when idle at lights or traffic it goes up after a few mins.......getting paranoid would be good to just flick it on when i feel in traffic or at idle before the thermo comes on.....at what temp to they normally come on 90 degrees?

Edited May 25, 2009 by blktoy35

[philbey]

You tell us what temperature it comes on at - Could be anywhere from 60Deg upwards. I'm gathering that you installed the switch, therefore you should know what it comes on at?

 

Further, do you ever notice it boil? Because if it only kicks in at 95-100 degrees, you'd most likely get some boiling. I'd say there's a chance your crappy gauge is giving crappy readings.

 

The switch is easy. Study the wiring diagram for the Relay circuit. Depending what switch you have (Close at temperature or Open at temperature) you just need a parallel circuit to the relay with a manual switch in it.

[love ke70]

those temps sound fine, and philbey, it a pressurised system with coolant, which both raise boiling point, so you can't say its gonna be boiling below 100, which is when water does.

ive seen some cars at 118 and not boiling.

you could change the trigger switch from what sounds like a 95/85 to a 90/85 but i wouldnt bother.

how is it wired up currently?

theres a good diagram on toymods wiring up a thermo with a seperate switch

[blktoy35]

there doesnt appear to be boiling and no coolant is going back into the overflow.... i take it my gauge maybe a little off the fan is probaly going off at 95d.... i didnt wire the thing up....... i had a muck around earlier. At the thermostat housing i d/c a plug running one wire, this triggered the fan to stay on all the time.... how does that work? can a switch be connected using this wire?? sorry I'm not to cluey when it come to how the thermo works I'm used the to k engine!

[the witzl]

95*C is a good temperature to be switching on the thermofan. Personally i wouldnt mess with it, its working fine now isnt it?

Does it cool down when the fan turns on?

 

If you answered yes to the above questions, then don't touch it.

[philbey]

those temps sound fine, and philbey, it a pressurised system with coolant, which both raise boiling point, so you can't say its gonna be boiling below 100, which is when water does.

ive seen some cars at 118 and not boiling.

you could change the trigger switch from what sounds like a 95/85 to a 90/85 but i wouldnt bother.

 

I'm well aware of that. Boiling point with a 13PSI radiator cap will be around the 120 mark. What I would be more concerned about is the hysteresis of the system: IE once the fan switches on, what sort of temperature overshoot will be likely?

 

If you have a small radiator with not much capacity (ie stock KE35) and a higher temp switch, you may have some temperature overshoot before the fan manages to cool it enough.

 

I wouldn't worry about it this time of year. Keep an eye on it during summer, and spend 50 bucks on a better gauge! Failing that, change the switch

 

EDIT - Put a new rad cap in for peace of mind as well.

Edited May 26, 2009 by philbey