Review on ACDelco 252 994 Professional Water Pump by Jose Strong

The only thing I could give a star for is the fact that the O-ring at the top of the coolant bypass pipe (where it enters the T-Stat housing) is a slightly larger one has diameter . . The wall thickness is thick, but the o-ring is loose enough to slip during installation. A slightly smaller o-ring of the same wall thickness provided by a local hardware store solved the problem. In and out in 4 hours, plus two more times the whole thing was taken apart to play around with a silly oversized o-ring. Do yourself a favor and get the right (smaller) size o-ring before you start. Oh, and we hope AC Delco figured out how to hold the pump shaft to the impeller and pinion. The landing press used when the pump was last replaced (110,000 miles ago) was spinning and stopped moving the coolant.