Hey guys, Newbie on Deck!
I've been in process of draining and flushing the cooling system of my 97 Formula and when I get to the point where you are supposed to start the engine with the radiator cap off, the coolant level rises and spills over the radiator and I can't for the life of me figure out why. Is the thermostat stuck or is something backfeeding into the radiator?? Any help you might have is GREATLY appreciated!

 

I'd check the overflow tank first, it might be too full.

 

This is completely normal. As the temp. goes up the hot water from the engine is releast into the rad. there it expands.

FYI: Read if you want.
If you want to experiment. Fill the rad. with plain water, drain closed of course, cap off. Start the engine cold and watch the water, use a flash light. At first there should be almost no movement, maybe some slight level change. As the temp. goes up and the thermostat starts to open you will see the water start moving though the rad., very shortly after the level will rise and over flow as the hot water and air from the engine are released into the rad. After this the water will go back down quite a bit. It's at this point that you start to top off the rad. Note, you may get several cycles of overflowing as the thermostat opens and closes. This is from both the hot water and air being released into the rad. After the system get fully warmed up things should settle down and you should have a nice even flow thohg the rad.

 

Cool, thanks for the quick tips. I checked the overflow tank and the reading was way past the FULL HOT line so hopefully that is what the problem is. Any ideas on how to get the excess fluid out of the tank???

 

Turkey Baster is a slow but easy way since most people have one of these.