93 explorer compression test

I have a 93 explorer and am having problems with the pressure in the radiator. When it warms up all the fluid is pushed into the res. and then runs all over the place.

The only thing i can come up with is a blown head gasket or cracked block or head where i think there is compression leaking into the coolant making the pressure rise in the radiator.

I have never done a compression check before so what i came up with is at first stroke on the cylinders was 90lbs. then it would go to 120lbs.
exept for the 6th cylinder which started at 30lbs. then gradually went to 120lbs. could this be the leak? Can anyone give me some advise on any other test i could do before tearing into the engine?

did you do a wet compression test to determine if it's your rings, or valves? a table spoon of oil will do. But to me it sounds like you engine is in need of an overhaul, or just a new engine.

I just did a compression test on my 94 explorer 4.0, and all cylinders started off at 90-100 and ended at 160-170. so like i said you engine sounds really low, but i would suggest comsulting an autoshop before you do anything.