Originally Posted by Wood Butcher
I believe it's 'Blowby'. Blowby is created by, someone correct me if I'm wrong, too much oil pressure.
Actually, wrong .. it's crankcase pressure ..
Originally Posted by sasquatch3805
snowman, you are exactly right... if it's the 4.2 then welcome to your new life, if not then you can fix it fairly easily by replacing what snowman said
Not exactly .. it can be sticky compression rings or sticky oil control rings, could also be worn valve guides.
All engines (even new ones) will suffer from ring blowby to some extent .. that's why engines use some form of PCV or CCV vent system.
Basically, an engine crankcase needs fresh air in and contaminated/exhaust air sucked out .. if this system fails somewhere due to clogged/broken/leaky pipes on the "sucking side" the "clean air in side" will be venting oily air into the airbox.
I would check the pipes .. check the PCV valve and elbows and seals for leaks (for CCV there is no valve) .. check the dipstick is firmly in place (yes air will be drawn in here .. look for a rusty dipstick). Is the valve cover leaking ??
If all is well with the PCV/CCV system then check the cylinder compressions .. this will show if it's leaking back into the crankcase. If they are within limits (and also fairly even across the set) I would doubt anything is wrong here .. but if you have a low one that could be your problem.
I would make sure the fumes are being sucked back into the inlet manifold.
Check the engine oil .. incorrect or dirty oil will cause the piston rings to stick up. Is it really black .. (sign of carbon getting past rings) .. change it a few times and see if it makes a difference.
Check compressions .. this will show if the engine has compression problems .. either a broken (or sticking) ring, or a scored cylinder, or it's just plain worn out.
For what it's worth .. mine was fuming really badly, leaking out the valve cover. I fixed the PCV stuff and now it's fine . ..