hi guys,
I've got a bit of a puzzling problem i was hoping you could help me solve. I own a 1995 bronco with a 5.0. I just recently completed my motor swap into a fresh 5.0. along with a new water pump and radiator. The donor motor is a 5.0. H.0. out of a 1988 Lincoln(80,00 Rebuilt .040 over)My question is why is my cooling system pushing coolant over the top of the overflow tank? The coolant in the tank is ice cold and the upper radiator hose is luke warm and the lower is cooler than that. The thermostat is new too. The truck does this without overheating. The temp gauge stays on the "O" or the "R". I have the supercooling package and the larger fan if this helps. I tried some of that blue devil stuff and it didn't seem to work, even after i drove the truck with no thermostat in it. Still puked the fluid out, at least the coolant was hot this time. I can idle the truck all day long and it won't happen, it only happens if i drive it for awhile. If i can't figure this out i'm going to have to scrap the truck and I really don't want to do that. Any help would be greatly appreciated guys. Ths truck is my daily driver.
p.s. When I originally got the motor and replaced all the gaskets and seals. When I Did the head gaskets I improperly torqued them and didn't torque them down all the way. I found this out after finishing the swap. So i tore the engine back down and torqued the head gaskets down to 85 ft-lbs. Could this be were my problem is? It would be nice if the problem was as simple as a head gasket change.

 

Just read the updated post after replying to the older thread. I think it might have to do with the climate control. If I were you, I'd drain the system and try again before replacing a brand new gasket. As you know, there's a lot of work to get down there. Refill the system, let the air bubble out while the radiator cap is off, add a little more mix...keep going until the fluid level is at a constant level around the relief line running to the res. tank. Start the truck with the res. tank cap off and run the heater full blast for a few minutes.

Smooth was right, even if there were air bubbles in the system from the initial fill, they should have escaped right away. Maybe someone who knows more about the heating system can help out here and possibly save you some time... anyone with extensive heating system knowledge?

 

Did you run the motor at the improper torque? What were they tightened down to? If it was too little it's possible the compression pushed into the coolant passage and that's why it's bubbling into the overflow but it's also possible that not all the air is out of the system.

I agree with running the motor until it's nice and warmed up with the cap off, topping it off along the way until you're sure all the air is out. You may or may not see bubbles in the coolant as it's bleeding out. Cap it off when it looks like the air is out and see if it continues out into the overflow.

Run the heater hot what you do this too. Dunno if it makes a difference or not but it wouldn't hurt.

 

I would take the radiator cap off, cover the radiator with a piece of card board, let the engine idle (and warm up) and watch the coolant in the radiator. As it warms up it should expel some coolant, but not a whole lot.

Do that, and post what you see.

When the coolant gets close to operating temperature, you should put the cap back, and then stop the engine.

 

Correct me if I am wrong but aint there some sort deal with the direction of rotation of the water pump........just a thought.

Other than that........I would at this point have to re-torque the head bolts in proper sequence just to make sure.....Next I think I would pressure test the system. Then drain it and refill, and hope for the best.