The blowby out of my oil fill is massive

[Rawze]

#1 cause = soot problems clogging oil filters because the engine running bad...

If changing the oil/filters makes the pressure come back, it is a problem with the engine (running bad) making too much soot.

You need to make sure the truck does not have excess soot problems. Excess soot will build up in the motor and clog up the oil filters making the oil pressure drop off from its normal 35~ish going down the road to as low as 32 or less after 10,000 of maybe 12,000 miles or more. This is a very bad situation to be in and it will cause large amounts of excessive engine wear until the excess soot problem is fixed.

Not only does the excess soot issue/problems need repairing, but the engine needs some consecutive oil changed to flush out all the buildup too. Change the oil at 3,000 mile intervals for the next 3 or 4 oil changes to reverse the excess buildup + do whatever is necessary to fix the soot issues that caused it to begin with. Otherwise, you will just be driving it around with it eating the internals and packing up cross-channels/chew up cams.

here is some related info: http://rawze.com/forums/showthread.php?t...18#pid6718