overheating/radiator question, need help!

[monkiboy]

basic info: 89 coupe, new water pump bout a year ago, new thermostat today, new oem radiator bout two years ago. fan shroud has been removed and electric fans are installed run by switch in car...

okay so, lately whenever i drive her for more than twenty minutes at a time, she'll be fine while im driving, but when i turn the car off the radiator will start pushing coolant/water back into the resevoir. and today i wasn't paying attention, and it filled the resevoir after i had left it in the carport with boiling hot water and over filled and started steaming outta the hood. i thought it was the thermostat wasn't opening or something or it went faulty so i replaced it, still, the radiator will suck water while i drive it, normal i guess, and then pushes it back, sometimes a lot, like today back into the resevoir, i never heard of boiling hot water being pushed into the resevoir. anyways, is there a dump pipe or something from the radiator that might be clugged or shut off that needs to be opened to let excess water out or something? DO I NEED A NEW RADIATOR or WATERPUMP? any help is appreciated.

if i need a new radiator ill just buy the koyo in the gb, this should help shouldnt it? thanks.

[UcanTry]

i had the same prob, my car was pushing collant to the overflow tank, after it was drove, what happen is we put it on the dyno and emtyed the overflow tank, did a pull on the dyno, and the thing filled up almost all the way, turned out to be the head gasket was messed up, and the also the head was lifting off the block, anyways it was a mightmare. before i found out what it was i replace the water pump, thermosate etc.....anyways just saying it might have something too do with the headgasket

[monkiboy]

cant be good.... anyone else?

[SirWarrior]

go to a mechanic, they can pressure test your cooling system and be able to say if you got issues.
also if you take the cap off, and you see bubbles in there as the engine is running, its the headgasket.
Guess How I know?

[Tucker]

I had a similar situation and after a quick trip to the mechanic to get it pressure tested, I replaced the leaky water pump and everything's fine now. The moral of the story is to get it pressure tested to find out what's wrong.