nolareese

I'm having a lot of coolant rush into my overflow when I turn off my engine. It is not running hot and I have replaced the radiator(about a year ago), LIM, and thought it was my thermostat which I just replaced. It is not running hot and I don't think I have a leak (at least not one that I can se) but I don't know what the problem is. Any help will be appreciated

tech2

if the rad cap (or reservoir cap if it uses a threaded cap on the reservoir in place of the rad cap) doesn't seal the system it will do that. test or replace the rad cap.

nolareese

I am going to test that as well as a pressure test the radiator tomorrow(to see if there is a slow leak some where). I did flush out my heater core this past winter because I had no heat, which worked but if there is air in the heater core, would that cause my problem?

tech2

no. air in the system would cause no heat at idle

nolareese

Can it be that I am not burping the system to get the air out properly because I am doing it only on a slight incline? By the way thank you for your help.

tech2

no.
Based on your description on it not overheating and the reservoir filling; imo what is happening is the system is overheating at normal operating temperature. What that means is, the coolant boiling point has dropped because the system can't pressurize itself; due to the rad cap not sealing the system. Every 1 psi the system pressurizes = 3*C raised bp...so x that by a 15psi system.
If your run an engine with the cap removed it will eventually boil over at approx 100*C.


the only reason coolant fills the reservoir is when it overheats; its just overheating at normal operating temp.


I could be wrong, but that's where I would start. a rad cap is cheap and easy and so is a cooling system pressure test.

nolareese

I pressure test the system and there was a small hole in one of the heater core hoses(out flow)which was spraying on top of the engine and being blown off while I was driving it. So that is why I didn't see any puddles or drips. Thanks for your help