I have a 1987 s10 blazer. Getting anti freeze in the oil pan. My question is how do I determine if its a head gasket or a intake gasket? We did a pressure test on the radiator and it seems to be holding pressure.

It is your intake buddy gms plastic gaskets go south fast.especially the dexcool models. if you take off the radiator cap and you see brown you got a gasket eaten somewhere but mostly is your getting it in the oil pan it is your intake leaking
.hope this points ya in the right direction.