COOLANT BOILING

[Mbrooks420]

It’ll boil at a much lower temp without holding pressure. It’s the entire reason coolant systems are pressurized.

 

[Yorgo52]

So - the cap was stuck open? And that was letting air into the system although the recovery tank had fluid in it?
Am I the only one that thinks that victory has been declared prematurely unless pulling the hose while it was running shot something out?
Having a hard time wrapping my head around this one.

Radiator cap wasn't stuck open but after engine was hot and I turned off ignition, I noticed small amounts of coolant leaking out around the cap so if coolant could leak out, air could get in. I don't believe it was boiling from overheating, rather than air getting into the system through a faulty rad cap and bubbling in the overflow tank. Anyway, cap was replaced several days ago and haven't had a problem since.

 

[Yorgo52]

It’ll boil at a much lower temp without holding pressure. It’s the entire reason coolant systems are pressurized.

I don't think it was boiling. I think air was getting into the system and bubbling. That's why no overheating on temp gauge. Whatever it was, new rad cap solved the problem.

 

[Mbrooks420]

I think it was boiling due to why I explained earlier. If air (and coolant) were leaking out of the cap it should get pushed into the overflow tank and just sit in there. It doesn’t have to overheat to boil at atmosphere.

Remember, it’s half alcohol, so the boiling point is significantly lower than water.