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Electric Fan Project - question about thermostat installation

timbeam

timbeam

Member
I've got most of my parts together for the swap to an electric fan and as I go through the steps in my head, there is one thing I have yet to figure out: where to mount the thermostat switch. It is the the type that is designed to mount in the cylinder head of the engine or any mounting in the water jacket. It has a 3/8" pipe thread. What are my options? Do I install a "T" where the temperature sending unit is mounted and share that spot between the two?

I want to get this project done this weekend so I'll be ready for Cars & Coffee on Nov 6th!
 
If you have only one opening in the intake, you can do one in the thermostat housing. That is where mine is. Removed the allen plug and check the thread match.
 
Thanks AzPete. Sadly, mine doesn't have the threaded 5/8" port there but only an indentation where it could be drilled and tapped, I guess. I found one on-line that has the threaded port like you are describing. I was about to order it when I remembered something different about the one I have: My manifold is a C5AE-9425-M which like many of the early manifolds is machined with the thermostat pocket on the manifold side, so the housing I have has a flat surface where is connects to the manifold. Maybe I should just get the new one and grind down the surface...

A toggle switch under the dash is looking better and better...
 
Check your local auto zone or other parts house for the correct thermostat housing....might surprise you.

I do not like the idea of a "T" fitting either. Toggle switch....just do not forget.
 
I ordered the new thermostat housing. I'll make it work.

Yesterday, I had the fan all mounted and found it was 3/8" too thick. The nice people I had ordered the fan from were great though. They're sending a replacement that will fit out Monday morning. The dimensions are all the same except for the motor so all the work I did on the mounting brackets wasn't a waste.

If you ever are going to order a Spal fan, I would recommend getting it from Street Rods by Michael (http://www.srbymichael.com/). Their prices and good and Rose is a super nice lady and knowledgeable too.

Today, I wired the relay and its all set to go except for the wires that go to the ignition and the thermostat switch (I'll do the toggle until I get the new thermostat housing). Can't I pick up the ignition at either the right side (small terminal) of the starter relay or the + of the coil?
 
Do not take power from the coil. I would say to use the STA output on the back of the alt. This would only have power if the engine is running as long as it is a stock wired unit. You are using a relay from the battery and using the toggle to power the relay....right?

Which fan did you order and what are they sending now?
 
It's a Spal Relay. I've got the wires (big) providing power to the fan wired: from the positiive side of the battery through a 30 amp fuse to the relay (yellow wire), then the the other (red wire) from the relay to the fan, and the black from the fan grounded. The other 2 wires providing control is what I've yet to wire. The grey will go to the thermistor (toggle for now) the other (orange) I assuming needs a switched 12v (low current needed here) source since they show it wired to ignition.

The fan I tried was 16" high-powered curved blade 3.39" thick. The replacement is the mid-powered also 16" but with straight blades and is about 2.48" thick. Other than the motor thickness the dimensions are the same.
 
Finished! As I had posted in the Event Forum, it was down to the wire to be ready for the Cars & Coffee. Friday afternoon I had given up on going but the UPS guy showed up at 6:30PM with the replacement fan. At 12:15 it was done. It performed flawlessly on Saturday and Cars & Coffee was a blast! Well worth the extra effort.

I ended up wiring it "hot" so it will continue to run after I shut the engine off. Within 5 minutes I could take the radiator cap off...

Here are some pictures:
 
Always nice when a plan comes together.

Be careful with it wired hot. Some have had problems with the battery being run down.
 
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