Guys,

My radiator overheats when running in park. There is a variable thermostat to turn on the fan as the radiator gets hot that came with the truck. I need suggestions on how to attach it to the radiator body.

Thanks in advance...

 

I see I have 39 views and no suggestions. Maybe more information will help. The variable thermostat has a 2" capillary tube. I don't have any hardware with it to attach, Could I build a strap and weld it on to hold the tube?

 

I have tried the cap tube fan switch set up before, but it did not work well for me. It was probably because I had a brand new, stock style radiator, which I refused to push the cap tube thru the fins. So I tried mounting it in various locations. All in all I could not make it work very well that way. Since there is no air movement when the vehicle was sitting still the cap tube would not sense the heat thus the engine would overheat. This was even with it installed inside the fan schroud.
I finally went with a water temp switch which I was able to install in the thermostat housing in my 302. It made all the difference in the world. You can get one for $30 from
Watsons Street Works part # SP195TS. Phone is 8668590513. It works great for me. Hopefully you can find a good place (3/8") to thread it into your engines water jacket. Maybe you can even Tee it in with your water temp sensor gauge. This switch goes on at 195 and off at 180. Another advantage of using a temp switch sensor is you don't have to fiddle around with the fan on and off settings. If a guy is willing to poke a cap tube thru the radiator fins, or some you actually insert into the top hose, I am sure they work fine. The main thing is the cap tube has to be completely exposed to the heat source, not just just placed near it (in my experience).

 

When I use that style switch I put the capillary tube in the fins next to the radiator hose that connects to the thermostat outlet (usually the upper hose) and then adjust for fan on at 190 degress. Works fine for me, but I do put a tie wrap on the wiring somewhere close ot the tube to keep it from coming out of the radiator. The fins will hold it but if the tube wiggles it will eventually fall out.
Do you already have a fan and adding an electric as a fix? If you are overheating in park with a mechanical fan you need a fan shroud to get the fan pulling air across the radiator core. If you already have a shroud then there is a coolant flow issue, possibly a plugged raditor or water pump issue.

 

BigBlueCat, more info usually gets the better answer. For example, what engine and trans? Does your engine have an engine driven fan and shroud? Is there a fan clutch or direct drive fan? Does the radiator also cool the trans? Do you have an a/c condenser in front of the radiator? Is you electric fan in front or behind the radiator? What size electric fan?

 

Hey Bigblue,
Welcome. We had a lot of issues getting our fan to come on
at the correct temp.. Blew a couple of the in-line fuseable links etc.

We just wired the fan directly to come on at ignition. We both live in Texas & it's hot pretty much hot all the time here. I may go back through & re-wire the temp. sensor etc. but for now we are happy & the truck is cool in Austin.

Ben in Austin
1950 F1

 

Guys,

I finally used the right search criteria "attach a capillary tube to a radiator". Several instruction documents will be listed on the page. Basically all you do is:
1. Remove radiator clamp and hose.
2. Insert thermostat probe into radiator hose.
3. Place capillary tube on radiator inlet tube so the probe itself will remain positioned in the hose. Place the foam pad between the capillary tube and the radiator inlet tube.
4. Carefully install radiator hose and tighten hose clamp.
5. It is recommended that a screw type hose clamp is used for correct sealing. Factory type clamps can leak.

Thanks to those that gave advise, it was appreciated.

 

Not sure what stage of construction your truck is in, but if the radiator is dry, take it to a shop and have them solder on a bung for a screw-in thermal switch. Bosch provides single and dual-temp switches for the OEMs, they are very reliable and not as likely to leak as sliding a cap tube into a hose.

 

X2 On this advice ! Use the thermal switch and if you can't thread it into the intake manifold, do what was suggested above with the radiator. And have flow test it while it's there.

 

I'm not sure what your truck is but that is how I set up my '50 F2 239 V8 and it works fine. Make sure that the fine copper wire from the capillary tube to the fan switch does not touch any metal or it may give you a false reading. I tie strapped mine into a wiring harness.


P.S. If you click on "User CP" and then on "edit signature" you can add your basic vehicle information and you will get faster answers.