My son's new '65 has us both looking for answers and help. It has an overheating problem that we have tried all the suggestions from the Forum's archives: radiator re-cored, new stat (in the right direction), timing and compression OK, no hose kinking or colapsing problems. I even added a 8 blade fan AND an electric fan with only marginal success- still boils over often. It seems to run fine otherwise.

Here is possibly one area that you experienced guys can help us with: Someone had replaced the original 289 with a 302, reported to be from a '72 truck. It still has some smog control pipes that go into the heads. Someone had tried to plug them with some poorly fitting plugs, I replaced those with heat resistant plugs. Other than that, there is no more emission stuff left on it. Any chance the smog set up could be causing us problems? What else? I would appreciate your collective input, like all of you, he loves his ride and Dad does too. Thanks!

 

could be the block needs a good flushing out. perhaps the water pump is shot also. Dupont used to make a two part cooling system flush that the do it yourselfer could use that worked well. first part is a mild oxalic acid that you add and leave it and run for 1/2 hour or so. then you neutralize this after draining it out with a soda type powder and let it run for another few minutes. then drain and flush out with fresh cold water and refill with fresh coolant.
do you have a coolant recovery tank on it? if not, I would get one from a junkyard or auto parts store and use it. it is normal for a full cold radiator to overflow and blow out coolant as the temperature comes up to normal and the coolant expands. the recovery bottle catches this overflow, and when the engine is off, as it cools it will draw a vacuum and suck the excess coolant back up into the radiator so it's there next time you start the car. another thing to check is the radiator pressure cap, it should be rated for 13-16 psi pressure or there about. if the cap is bad and not holding pressure, then the coolant will boil at a lower temperature than it would with the proper pressure cap on the radiator. does the fan have a shroud around it, if not, get one as this makes the fan much more efficient at pulling the air through the radiator. also make sure the front side of the radiator coil is clean and free of debris, dead bugs, etc. as this restricts air flow also. also check the actual temperature of the coolant with a thermometer and compare this reading with the temp gauge if it has one. 200 degrees or less should be about right with no pressure on the system.

 

Damn roundman i wish every member was as knowledgeable as yourself.LOL

You left no stones unturned on that one.

That should definately cover any problems you are having its one of the things he mentioned.Sounds like a waterpump to me.You changed all else might as well try that too.Get an aluminum pump and i suggest buying that plate that rivets to the impeller as well that will move up to 30% more coolant over stock.