350 overheating probs

[BigRed87]

Just got my 60 out of the shop, drove it a few miles and noticed it was getting hot, by the time I got it home, it was boiling over. Called the guy who put it in, and he said that it did not overheat when they let it idle with the A/C on for over an hour. What might it be? Not enough air (running a clutch fan), or the radiator itself, the mechanic said that the thermostat might be stuck, plausible?

It only overheats when driving on the highway, it does not while at idle or driving under 45mph.

 

[Texican]

Heating at hiway speeds usually points to radiator stopped up or not big enough, since I know of several 350 powered 60's with stock radiators I would imagine yours needs attention.
Butch

 

[BigRed87]

I had it flushed before it was reinstalled.

 

[Texican]

Flushing may not do any good if it has mineral deposits in there, a good old time radiator guy like I have can hook it up to his water/air blaster and tell real quick by the amount of water travels thru when he shoots the air to it if it is flowing good.
Don't chance ruining a good motor though, order a new one if in doubt
Butch

 

[saint60]

make sure your water pump is functioning properly as well. it has to either be the rad or the pump. if you are in doubt about the thermostat, change it. it takes about 5 minutes and they cost about $10. i don't think it's that though. butch is right about the deposits. i have had one flushed, over heat, replaced, and problem solved. that is wierd that it does it at highway speed with all that air and not standing still. hmmm...

 

[saint60]

oh and with that thread i just put on the huggies pullups as a junior. yeah!!!

 

[BigRed87]

Took it by the guy who helped me build the engine, and he figured it out. We had used the stock fan shroud on the rad, which was 2" off center, which let the fan pull enough air while at idle, but did not allow enough air flow while driving. And the fan is too far from the radiator, so I ordered an electric.