93 3.0 4 door. 137, 000. miles.

I just had the Radiator R&R'd about five weeks ago.
I has a life time warr. on it.
It went in about the same spot.
Looking at the front of car. RT side plastic tank. 4" down from top at the center of the side.
The old one: right where the core meet the tank. inside top left.

Why though? Steam build up.
Head gasket?

Will it happen again.
How can I diagnose.

THanks IN advance.
Hardtail

Is the radiator cap new? How many lbs. is the cap rated for? Sounds like a defective radiator.

Next time get all metal.......