coolant coming out of radiator cap

[Prey]

last night at the races, when the engine warmed up coolant would start shooting out of the radiator cap

the cap seemed to fit ok, not super tight, and i know these have a set value for PSI, so my question is this, could this have something to do with the water pump creating more pressure in the system than there should be?

i would have thought is it was the cap, i would have seen a more gradual deteriotion rather than all at once, but i can be wrong about that too.

any help would be appreciated.

[joedirt]

Make sure it is all the way on never heard of this before.

[Prey]

i had taken the cap off and put it back on 4-5 times in between pracitces and racing and what not, i am sure it was on right.

there are 2 things i can think of causing this.

the little pegs on the bottom of the cap are bent/the radiator may be wore where those little pegs catch to tighten the cap

system pressure....caused by ???

there maybe some other reasons that i dont know of.