coolant problem sti import v4

Jul 19, 2003 2 Replies

well my mech fitted the new thermostat and I got a new header tank!. but I went for a drive a few days later after I checked the coolant level, and it was still pushing the new coolant out of the expansion tank the one near the battery!. the coolant goes down in the header tank to the expansion tank but does Not go back to the engine or header tank! what is going on??.. .



should I put a old thermostat in with the stat part open so coolant flows around the engine ect.. . and block the expansion tank over flow pipe on the top off??.. .



is it a good idea to to do this??? .. .



help please......... .


Hi,

Any chance there's some foreign material in the overflow tank that is acting like a one way valve, stopping the reverse flow into the radiator when things cool?

I've seen leaves, bits of paper or plastic and all kinds of other crud (including a dead mouse!) in overflow tanks over the years. You might want to remove the tank, rinse and drain it, and remove the little hose and make sure it's not blocked, too.

HTH,

Rick

Hey, I had a similar problem with my Forester, and new hose clamp fixed the problem. What happens is that when the coolant expands it flows into overflow bottle, and when it cools down it suppose to go back into the radiator. But if you have a tiny air leak somewhere, air will get sucked back in since it's much lighter then coolant, and coolant will remain in the overflow tank. There are several things to check: radiator cap (doesn't seal properly), hose clamps, and could be something related your thermostat replacement where something wasn't sealed properly (that's what I would check first if you didn't have the problem prior).... Good luck! Regards, Viktor.

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