The Stovebolt Site Forums The Shop Area Engine Shop 216 over heating

After finally getting my 216 running really good, all of a sudden it is over heating. Currently no thermostat, replaced the water pump...no change! Now, it sat since 1972 before my attention. Whats the chance I plugged the radiator with scale or rust or something?

You need to flush the radiator if it's been sitting that long.I would take it to the local shop to also have it tested .When the radiator is in the shop you may want to look at the water passages removed hoses and thermostat housing .Use a water hose to flush the engine water passage you want it all clean .Good luck .

"Currently no thermostat"
You definitely need a thermostat and be sure to check the opening temp in a pan of water on the stove with a good thermometer before you install it.

Found the prob...radiator was plugged. Took it out, ran garden hose in it upside down, lots of "stuff" came out. Probably from sitting so long. Re-installed with new coolant. Doesn't run any hotter than about 160 now.

Ok....here we go again. Overheating! Old radiator was plugged. Bought new one , flushed engine as well as I could. New rad performed flawlessly...until today! Still do not have many miles on truck since getting back on road. Water/antifreeze has mostly a rust color to it. There has got to be a way to flush this old engine WITHOUT running the fluid thru the rad. I have drained and re-filled the antifreeze 4 times now. Still have bad looking coolant. Has anyone ever contrived a way to flow water and flush fluid thru the engine but by/passing the rad, even if pausing to let it cool occasionally. I will probably have to have this new rad professionally cleaned now! I haven't even had enough time to use the Peak flush and clean product

After refilling the cooling system, sometimes an air-pocket can get trapped under the thermostat, which will prevent it from opening, even when it's hot (the air doesn't transfer heat nearly as efficiently to the thermostat as water does, so it doesn't "read" hot enough to open.) Does it sound like that's what could now be happening?

Common practice is to drill one or two small holes in the side flange of the thermostat, to allow air to escape to the top of the radiator and out as the water circulates.

Otherwise, sounds like just a lot of flushing is necessary.

-Michael

I would also check your vacuum advance and timing. A bad one can help cause over heating.

Ditto that, plus fuel delivery. I'll never forget my 216 gradually overheating from a lean condition, while it ran worse and worse. My buddy reached over and pulled the choke out a little. The difference was immediate. Cured it right up.

Heck - just check and fix EVERYTHING, and it won't overheat anymore! ;-)

-Michael

You probably have heard this already, but if your truck has been sitting so long you can bet the the block needs a good thorough flushing. I have done this on a number of old motors, and finally I learned that if you haven't opened up the rear petcock on the block (down behind the steering shaft)you haven't really flushed it. When I have finally got that drain opened usually it is so gummed up down there that nothing will drain. I've had to go in with a chopped off clotheshanger to loosen the crud that accumulates back there. When it finally starts to drain it will be pure mud. Failure to flush this crap out can lead to overheating and a cracked block. Don't ask how I know this last part.

Karl