The Stovebolt Site Forums The Shop Area The Electrical Bay Temperature Switch for Fan

Well, my 43 year old radiator finally gave up the ghost so I've decided to upgrade to a new aluminum one with an electric fan since I'll be dropping in a 350 some time this winter. My current quandry is that I will be running the 230 until the 350 is built and I don't know where to put the temperature switch. The hole in the water neck is where my temperature sending unit is located. There appears to be a pipe plug on the intake side of the block about half way back that goes into the water jacket and I was thinking of putting it there. Is this a good location?

You don't have a plug on the head, just above the #2 Int and Ex manifold runners. That is where my temp gauge send unit has always been.
If the 230 is soon to be replaced, why bother. With the cooler fall weather, you shouldn't need an electric fan.

You didn't have to remove the old fan to get the aluminum rad in did you???

The system I installed used a probe that pushed through the cooling fins on the radiator. I installed it near the outlet or lower radiator hose. You can buy a t-stat housing that has a threaded hole in it for a temp sensor and some intakes have an extra hole that is pluged with a pipe plug.
If you want to run the fan with the currant engine most parts stores carry an electric fan switch and relay kit for about $20.00. Its like the one I installed and you just push the probe through the fins on the radiator.

Richard he is in Texas Fall and Winter weather here can be 90 deg. F. lol

Let see...I don't HAVE to install the electric fan, I'm doing it for the best of all possible reasons...I want to! Likewise the larger alum radiator is not a must at this point (I could probably have my old one repaired), but I figured since I'm going to put the 350 in later anyway, why do things twice? If I set up the radiator and electric fan now it will be good to go when the 350 is ready. Speaking of the 350...it was already supposed to be in the truck but at this time it is a bare block sitting on my engine stand...my middle daughter's car had to have some work so my engine money went to that repair bill. I should be able to replinish my modest 'bolt fund by the end of the year and recommence work on the 350, but how do I know that one of my "spending helpers" (aka wife, kids, and Grandson) won't need something worse that I want a new engine? So, if I put a radiator setup in the truck capable of easily handling the 350 now, it's not an issue later, when and if I ever muster the funds to get it finished.

And Toyvo is right...90 deg in the middle of Winter is not unheard of down here. Thanks for the response guys.

Forgot to answer a couple of questions...

1.) The location in the head above #2 is where the pipe plug I referred to is located. My temp sending unit is located on the t-stat housing.
2.) I don't know if the old fan will have to come off or not since I only ordered the parts from Summit this morning, but I don't think that it will unless my tape measure lied (which it has done before).

The head sender would register a little hotter than the t-stat housing mounted sender. The head area was used on later trucks/cars for Transmission Controlled Spark. Brian

How did it work out? inquiring minds want to know

You don't want to use a block mounted sensor for a radiator fan. The thermostat is supposed to regulate the temperature in the block to within a few degrees of 180. You want the fan either in the water neck or on the radiator itself. Some radiator tanks come tapped for a sending unit- a lot of BMW's and other cars use tank mounted sensor switches.

The radiator worked out great! I have a small issue with when the fan kicks on, but that will be rectified shortly by swapping the temperature sender and the fan switch. I'll try and post picture later.