68 overheats. Why???

[zwoman]

My 68 has had an intermittent problem with overheating. The radiator was replaced, the water pump was replaced, and I can't tell you how many thermostats I have gone through.still I can't trust that the gauge won't peg at the most in-opportune time. Any suggestions?

 

[GDTrumbo]

First, is it really getting hot? or is the gauge messing with your head?
I used to have a '66 Coupe so 2 things come to mind. Check/replace the temp sending unit.
The second thing is a small silver instrument panel regulator that is mounted on the rear of the gauge cluster. It's about an 1" long and 3/8" wide. It just simply unplugs. If this little regulator is bad it will give you weird readings on various gauges in the panel.

Thats a couple things to check anyway. A good shop manual on this car will be indespensible.

Good Luck, GT

 

[rbohm]

i would first put a good mechanical gauge on first and see if it is really running hot. as stated the IVR could be going bad, or your factory gauge might be out of whack. next time you see the temp going up, check the oil pressure gauge and the fuel gauge as well and see if they are going in the opposite direction. my 66 had an IVR malfunction years ago, the temp gauge would peg at the top, and the oil pressure gauge would peg at the bottom. they would return to the proper reading after a few seconds though, but once i changed the IVR that just stopped.

 

[zwoman]

Thanks for the input. Yes it is definitely getting hot....boiling out of the overflow. I will check the IVR though. Sounds like something to check out.

 

[Rusty67]

A mechanical temp gauge is definately the way to go when troubleshooting this kind of thing. Do you have an overflow bottle or is it just bubbling over and then you have to refill the raditator later ?

 

[2+2GT]

The radiator was replaced
OK, good, with what type? 2-row? 3-row? 20"? 24"?

Do you have a fan shroud? What type fan?

the water pump was replaced
Surprisingly, this usually has no effect on cooling.

and I can't tell you how many thermostats I have gone through.
You should be using a genuine Ford 190° unit.

 

[68GEETEE]

on my 68 the fan was too far away from the radiator to be effective. It should be within about one inch from the radiator.

 

[2+2GT]

on my 68 the fan was too far away from the radiator to be effective. It should be within about one inch from the radiator.

Unless you have a fan shroud, then the fan tips should be centered in the opening.

 

[aug0202]

have you tried the radiator cap alot of times the springs get weak and fail to pressurize the radiator properly take it to autozone or advanced and they can test the cap for you for free