1988 Buick Regal

Hi. Did you add the full 5 quarts of oil when you changed it? There's usually some oil left in & around the engine when it drained. Yu should only add the first 4 qts, then wait 5min & check the level onthe dip stick. Add 1/4 qt. at a time every 5 min as neded after check'n the dip stick.

When you look at the oil dip stick does it have grayish colored water beads in the oil on the dip stick? If it does you most probably blow you head gasket.