b2200 engine troubles

i have an 88 Mazda b2200 and it has about 177k on it. recently the crank seal went out so i replaced it. it lasted not long and went out again, so i replaced it and about 5 min of running and it started leaking again. i know the seal was seated flush and no gouges and no grooves. the compression test did say the cylinders are a little week ( around 125-135) but that shouldn't cause that fast of blow back i don't think. someone suggested i replace the PCV valve since that could cause pressure to build up and blow the crank seal but im not familiar enough with engines to know. any help would be greatly appreciated. the oil just runs out so i cant drive it like that...

pcv valve will be attached directly on the valve cover or a hose coming out of it but usually excess pressure will push the seal out or leak at a old one like the rear main, its possible your crankshaft has a nick or droove the the front where seal ride or the drain hole it plugged, if your sure its the seal leakind and not the gasket holding the oil pump on you might need a crankshaft sleeve repair kit. its a think sleeve that fits over the end of the crank. you can get a new pcv and try it and make sure hose going to it is clear first

thanks for the reply, i tried the pcv valve and still leaked. the crankcase seems to have a lot of pressure on it its pushing oil into the air filter housing like crazy. i checked the shaft and housing but everything is smooth no nicks or gouges i think for some reason it has lots of pressure any guesses?

excess pressure is usually a symptom of worn rings. did you check the hose to the pcv? if you remove it and stick your finger over end with its running should feel suction