help please! rad/water trouble...

[Porker]

I have a '98 Boxster 2.5

Replaced both water Rads and AC Rads... still had a leak so I replaced hoses and clamps... now there are no leaks but when i open my water cap, the water overflows out of the bottle... a friend suspects this may be the head gasket?

Has anyone had this problem before or knows what it could be? Any guidance would be very much appreciated... Thanks.

[Paul]

Let's ask the easy questions first:

Is the tank overfilled? Should be below the max line when the engine is at operating temperature.

Are you removing the cap when the engine is cold? If removed while hot, coolant is likely to be lost.