Technical Odd over heating situation

This.

 

Ok just a thought. A friend of mine had the exact problem. What he found was the tubes of his after market aluminum radiator were "ballooned" out enough to trap air flow so at low speed the thing would over heat. He went through the same things you are. We found if by chance looking stright through the fins you could hardly see light. The thing is it looked perfectly fine otherwise. I can tell how frustrating it must be. But really sounds like airflow issue. If you look stright through you should be able to make out fine details of your engine almost like nothing is in the way. Good luck.

 

Maybe I missed it, but what rpm are you running, in gear, at idle?

 

I had the same problem. I did everything the others have suggested and nothing worked. Here's what to check. Start the car cold with the rad cap off. Look in the cap and see if there is any water movement, there should be none. Let it heat up normally and make sure you know the thermostat is open. I used one of those Harbor Freight heat guns for that. I even put a piece of cardboard in front of the rad so I knew it was hot.
Look in the rad and see if any water is moving. If none is raise the idle slightly like you have been doing at intersections. If you see water moving you have solved the problem.... Speed up the water pump. My engine had a 7-1/4" pulley. It now has a 6" pulley and the problem is gone. No coolant was going thru the rad at idle. Temp gauge goes up a little in heavy traffic during the summer, but it has NEVER heated up again. Good luck..

 

@Fedman gets the chicken dinner! Looking back it all makes more since than I'd like to admit.

It only took a little tweak and it's totally gone! Drove around for a good hour and it's stayed right at 180/190 and feeling good.

 

Great! Thanks for posting the fix.

 

So which was it?
Advance timing?
Increase RPM?
Vacuum hook up to ported or full manifold
A combo there of?

Fedman mentioned all three.

 

Oh sorry your right, I tweaked the timing. Didn't take much I feel silly for not having figured it out sooner.

 

Might be too lean @ idle. Like maybe the mixture screws are screwed all the way in. Only affects it at idle...cools off when revved up.

 

In gear your revs drop, fan spins slower, water pump spins so slow it is hardly pumping, and you overheat. Drop it in neutral, get the rpm to 800+ and see if the temp drops.