Does the coolant expansion tank have an overflow, above the MAX mark?
this is a 2005 civic LX, 1.7 auto

i ask because, when i pour coolant into expansion tank, and go above MAX, it comes back out somewhere

i can;t see where, but if the tank has an outlet port above MAX, that has to be it.

but it also has to be hidden so i can;t see it (yes i have the battery out so i can see at least that much of the side of the tank..)

and i can;t see any leaks from the radiator either.

all i can see is coolant coming from the frame member channel below the radiator.

if car is tilted to left it comes out left side. tilted to right, the right side.

original problem was, no water in radiator.

i was trying to diagnose it by filling expansion to the top, then water started coming out somewhere.
but i can see most of the tank, including its bottom, and it isn;t from there.

thanks!


wle

 

I think it just overflows around the cap. If the tank is constantly becoming overfull while the radiator becomes empty, that is often a bad head gasket. Pressure from the cylinders blowing through the gasket pushes the coolant out of the engine and overflows the tank.