Mazda Repair: 1990 mazda 626 engine, crank case, oil leaks

Question
I had major oil leaks that have all been fixed, gaskets and O-ring changed,new timing belt,water pump, all hoses replaced.  My mechanic now says that there is to much pressure in the engine to why I am blowing gaskets and seals. Do I need a new  engine?

Answer
Not my area of expertise but, No.  Pressure?  Excessive oil pressure can be due to the type oil and weight.  (ie 20w-50 in cold weather will take more pressure to flow than 5w-30 will in the same condition)  Also, pressure could be blow by in the crank case which is vented by the PCV valve (positive crankcase vent)  cleaning the flow tubing at this area or a new valve may be needed.