Electric fan question

[Flightman91]

Good morning folks,

I intend to swap from my stock metal fan to an electric one, and I have a couple things I need advice on.

First, does the spacer between the water pump pulley and fan come off or do I need to buy a new pulley?

Second, any suggestions on the best type of thermostat for this thing. There seem to be 3 or 4 different types. I'm looking for something simply and reliable, preferably with an over ride switch. Any thoughts or experiences would be greatly appreciated.

Thanks

[eggman918]

When using the electric fan in my Cummins swap I used a single wire thermostatic switch in the water jacket
https://www.summitracing.com/parts/aww-500880/overview/
the switch was used to control a heavy duty 12 volt relay that would handle the load of the fan
https://www.summitracing.com/parts/ctn-sn3885
I also wired a lighted override switch in the dash that also activated the relay.
One thing I found with the electric fan was that at low speed/high load conditions and when off road, having the fan properly shrouded was vital otherwise it tended to pull too much hot air from the engine compartment. If it were I I would look for a fan/fans with a shroud that covers the whole radiator
I finally ended up going to a electric clutch similar to an A/C clutch that is engine driven turning a 20" 10 blade fan from a Cummins stationary application,which moves a HUGE amount of air, it has a 210*/195* switch that allows the engine to run much cleaner with more power at lower boost yet when it kicks on it will drop the temp from 210/215 back to 190 in under a minute even when the truck in moving at walking speed.

[cep62]

The spacer comes off , you might need to tap it with a hammer.

[Flightman91]

Good to know about the spacer

I'm pretty stuck on the electric fan. I'm just not sure which kind of thermostat to use. I'm stuck between the ones that thread into a port, or the ones that stick into the radiator.

[eggman918]

I would use one that threads into the water jacket

[Flightman91]

I think my only open port is on the water neck, unless there's another one on a 390 somewhere besides the one on the intake.

[HIO Silver]

Are we discussing a temp sensor or thermostat? The latter is the device which regulates coolant flow thru the engine while the former is what provides a signal to the water temp gauge and/or electric fan switch.

The typical location for the water temp sensor is atop the intake manifold. A potential secondary location is the thermostat housing... some FE engines have a thermostat housing with a threaded boss for another or alternate location for the sensor/temp switch.

[Flightman91]

A thermostat to activate an electric cooling fan.

[Flightman91]

Anyone know what size fitting is in the water neck?

[Ranchero50]

Do the radiator probe, that way the fan only runs when the radiator needs cooling air flowing through it. There's a dead span between fan on and fan off, 10-15 degrees. You want the fan off to be above the T stat temp so the fan only runs when needed. Most aren't set up correctly and once they come on they stay running. The fan should cycle similar to OEM's.

[Flightman91]

Thanks for the advise. At the moment mine doesn't cycle at all since it's bolted to the water pump. I think I'm gonna go for radiator probe, sounds easier. I'll just have to order the right temperature.