intermitant overheating

[71HANKER]

Hey guys, im having a weird overheating problem. A while back the rear freeze plug started leaking on my 460, and i punched it out, flushed out the block and radiator with a hose and put a new brass one back in. I bought a coolant system flush kit and followed the procedure to flush the entire system. I then tried this coolant system leak fix crap called Blue Devil, mostly to prevent future leaky freeze plugs. The truck has never had a thermostat in it and now sometimes it takes 25 miles of highway driving to get hot or 5 miles of hard test driving. That Blue Devil stuff was like blue water and its supposed to coat everything in the coolant system, my friend put it in his john deere tractor and it fixed his cracked cylinder wall, keeping the water out of the cylinder. But im thinking my radiator must be plugged or maybe the flush worked loose some rust in the block? yesterday it hit 220 degrees and this really really made me mad. I have never trusted radiator fix products and now im kicking myself for giving in. What do you guys think?

[heep70]

The flush probably knocked a bunch of crap lose and yes like you said plugged that rad.

[71HANKER]

Yeah thats what i figured. Its my own dang fault. I got a good radiator guy though, that car rod out the radiator and fix it for about 30 bucks. looks like thats what im doing. thanks Heep.

[fordman]

some of that stop leak stuff will plug up the radiator. plus you may have flush stuff from the block into the radiator.

[heep70]

It will plug the heater core too

[willowbilly3]

Read all the other cooling system threads? Proper cooling system, clean it. Acid flush maybe, or power backflush if you can find someone to do it. THERMOSTAT, I don't care if it didn't have one before. Fan shroud. If you have a clutch fan make sure it is working properly. Have your radiator cap checked.

[71HANKER]

I had done the acid flush myself after i replaced a freeze plug. Has a flex fan on it, no clutch. it has a radiator shroud. radiator cap looks old, no thermostat in it. Ive had some people tell me that not having a thermostat will make it overheat because with no restriction, it allows the coolant to flow too fast through the system, not allowing proper time to cool down in the radiator. and i know that different pressure ratings on radiator caps affect temperature too. should i try a new thermostat and radiator cap before i decide to yank the radiator? couldn't hurt huh?

[fordman]

i would try that and see what happens. how does the radiator look inside when you look down into it. does it look clogged or dirty with chunks of white stuff around the tubes?