Water overflow

[tioga bandit]

I have recently got an 1952 8N. Ran a few years ago when parked. It is now running, but shortly after startup water starts coming up and out of the radiator. It has a new radiator. I followed notes on the
forums and put just enough 50/50 mix to cover the fins. I had the cap off top see if water pump was working. before thermostat opens the water starts coming out. I was thinking maybe a head gasket? checked
compression and it was 90-85-80-85 starting at 1.

 

[HFJ]

hi tioga. welcome to YT

your compression is low, but not drastically. mine is 90-90-90-85 and runs fine. ideal is ~ 125 for this engine.

well done with not overfilling it.

before i pulled the head, i'd pull the spark plugs. if you've got a bad head gasket, one or more of the plugs is likely to look steam cleaned. any white smoke coming out the exhaust pipe? any bubbling in the radiator before it overflows?

 

[tioga bandit]

All the plugs look normal. No smoke out of the exhaust and no water in the oil. I think there were some bubbles in the radiator. I am going to start it up today to check.

 

[tioga bandit]

Put water/coolant just to cover the core of the radiator. ran a few minutes and then it water rises up and out then goes back down. then rises up and out and goes down again. after doing this 3 times a little steam starts coming out and i turned the engine off. a few bubbles during the second cycle of that pattern.

 

[reomack]

It sounds like you have air trapped in the engine, though I have never heard of this in an N Ford. Try revving the engine to about 2000 rpms for a bit. This might force coolant through the engine fast enough to purge the air. That is if this is actually the problem.

 

[reomack]

You could also have combustion gasses leaking into the coolant system through either a crack in the block or a leaking head gasket.