Engine cooling issues

[J-440]

Evening all. I have a SPAL electric fan with a 180* switch that turns on automatically. The switch is mounted on the lower part of the radiator. I also have a 185* t-stat. My fan is not turning on obviously because the water temp in the radiator is cooler than the water in the motor. I know the switch needs to be mounted in the heads but I have no provisions to do that. My other option which I don't want to do is to mount the switch in the block, but the headers are pretty close and the block is shallow and not deep enough for the switch to thread into. Even with an extension for the switch to be mounted in the block, it would jut out too far and hit the header.
So here's my other plan. Do I need to get a lower temp switch (125*??) to have the fan kick on sooner or do I need a different t-stat? Thanks again for all the help.

[anthonys 69]

What is the car doing when you drive down the road does the engine actually over heat

[J-440]

It's not driving it's idling. I'm in the process of tuning my FAST XFI and am adjusting the timing and VE tables. But in the meantime, I get up around 200* and the fan is not turning on. I'm in Texas and in a semi-cool garage so these are also factors. I know the switch works, I'm just wondering if it's the wrong degrees.

[hifi875]

does the fast system have a output to activate fans. I know some do (ie. holley).

[Zspoiler]

Try having a manual override switch for a backup and watch your gauge.

[J-440]

You know hifi...this must be one of those days because I'm not thinking clearly. Too many beers yesterday maybe? Yeah I just checked my FAST instructions and there is a wire from the ECM that can be run to the temp switch. My electrical skills aren't that great so we'll see what else can happen. Guess I just solved my problem. Thanks again.

[Red67Mustang]

Typically the lower part of the radiator is the return side. You could consider moving the switch to the upper chamber of the radiator to read the hotter temp of the water coming to the radiator from the block.

I have the Holley HP EFI set to control the fan in my Mustang, but just as a back-up I also have a Flex-a-lite fan controller that's set to a slightly higher 'on' temp than the ECU is set for. Just belt and suspenders to make sure he fan comes on no matter what.

[SparkyRnD]

if you use a threaded port in the engine, that is best and most accurate usually. If you don't have any available ports in the intake, and don't want to make a dual port, then go with a probe style switch inserted into the hottest part of the radiator (as close as possible to where the upper inlet hose is). That will give you almost the exact same reading as a port in the intake, within a degree or two usually, and will be good for activating the fan(s). Also, make sure to wire the fan(s) directly to the battery on a fused circuit, and have the controller with relay activate them. That way they are getting full power.