1960 235 overheating questions

[nacho55]

Just seeing if anyone has some ideas (other than a head gasket replacement) for overheating on my 1960 inline 235
Little background, the truck was sitting since 1980something, so
Here's what has been done,
New fuel pump, fuel tank, rebuilt carb, new fuel line added inline fuel filter, New water pump, new thermostat, new radiator cap , & hoses.
It seems to run fine and idle in the driveway without getting warm, took it on the freeway and it stayed in the middle range of the gauge, soon as I exited the freeway the temp shot up and pegged it, I pulled to a gas station and let it cool of as steam was blowing into the overflow jug, added some more coolant and went on my way, got home and after it cooled enough I opened the cap and watched it run, and didn't see any bubbles so Im out of ideas.
It is running the stock fan, don't know if these trucks had a shroud from the factory, but mine doesn't,
Thanks for any input,

[dwcsr]

This may see odd and I've only seen this done on one truck but try putting a shield around the thermostat hosing. On this one truck it seems that when the engine was run on the highway it cooled down the tstat enough that it closed and then would over heat. They tried all the same things you did but the shield is what fixed it for them

[AcampoDave]

My first suggestion is to get a real guage with numbers at least until you can resolve this problem because the stock one is well....old and a bit ambiguous with only a C and H. Also in your repair list, you didn't mention anything about the radiator. Has it been sitting since the 80's too? And I do believe your truck came factory with a round metal shroud. At least V/8 models did. I always called tthem "the oil drum shroud."

[nacho55]

Yea it's a new aluminum radiator, it should have read, new radiator,&cap... But I think I fixed it or maybe just brandade fixed it, but as of now it's running cool and just a 1/4 over the cool mark on the gauge... So Here's what I did,
I took it for a drive around the block to try and get it hot and check it with my digital thermometer and see how hot it's getting, well right away it got hot just driving it less than a 1/2 mile so I pulled it over and checked and it was reading almost 200 at the thermostat housing, so I drove it back to the house and it was pegged, i decided to pull the thermostat out and see if it was opening, and it was but it looked kinda odd like it wasnt opening all the way and closed up quick after I pulled it out I even put it back in the housing and it wouldn't open back up, and I know the coolant was still hot, so I ran up to autozone and grabbed a "high perf mr gasket" 160degree thermostat and put it in and topped off the coolant and drove it around for over an hour and it never got past a 1/4 over from C, so I think I might have just got a defective thermostat or something, but now it's running right at 160 on the thermostat housing, so I'm excited I don't have to tear it apart further, but I'm going to see if I can find some pics of t
He orignal shroud and fab one up,

[AcampoDave]

That's cool you that you fixed it. (ha, ha cool get it? I kill myself sometimes) but really, I'm not surprised about the faulty therm. It was probably made in China anyhow. I use one of those Mr.Gaskets too. They remind me of the old Robertshaw units from back in the day. (Only not as good.) Hope you got it.

[nacho55]

Haha... Yea I guess you cannot expect a lot from a 3.99 thermostat from autozone... But the performance 12.99 one seems to be the hot ticket.... Or cool one in this case...

[rushautomotive]

I use a contact lens cleaner (boiler) and a thermometer to see what temp the thermostat boils at

[brokenspoke]

160 temp is way to cool for an engine to run...I like to use a thermostat that when it fails it stays open...My 2 cents worth

[joedoh]

glad you found the cause, I would like to add to please add a fan shroud, without a shroud its just an air beater.