SOLVED - Engine Failsafe after Valve Cover Seal Replacement for Blue Smoke

[McDonaldD]

I would not recommend disconnecting the PRV lines while the engine is running. You'd likely not do any damage, but its not worth the risk. Even if you managed to seal the intake ports, its not worth the risk of one of those fashioned-seals failing and being sucked into your engine...in such a case, you'd almost certainly need to rebuild your engine.

But, if you insist on doing so, you'd need to fashion some kind of air tight (vacuum tight) seal/cap for open ports on the intake manifold - where the PRV's hoses were disconnected - doing so would prevent oil from being drawn into the intake manifold but would not stop oil from splashing out of the valve cover via the PRVs. You would need plug these as well. However, the valve covers (and crankcase, in general) are not designed to be under pressure; which would be generated by blow-by gas during normal operation. Since there already seems to be a leak in the crankcase, you might get away with simply plugging the PRV's port because the leak may be large enough that it would prevent pressure from building, much in the same way it prevented a vacuum from forming...but you'd be gambling on this. I do not know the extent of damage that could be done if the crankcase were to become pressurized: it could be no damage, it could be negligible "damage" like a little more oil gets pushed out, or it could cause oil to be forced past piston rings and into your combustion chamber...

I have not fully reasoned through the implications of sealing off the PRV, even for testing. It certainly cannot be "good" for any of the crankcase seals...assuming it is sealed enough to build a pervasive pressure in the absence of a strong vacuum to evacuate such a pressure.

Also, I do not see what you would gain from disconnecting the PRVs.


With the engine off, you can check if oil is being drawn into the intake by:

1., disconnecting the plastic intake duct, attached to the throttle body,
2., pushing open the throttle plate,
3., and looking inside using a flashlight.

If the interior of the intake is even remotely wet and/or coated in oil, its coming from at least one of the PRVs; being the only possible source of oil in the intake, at least on the e53's N62. A similar test can be done by disconnecting the PRV's tube at the intake and checking for oil stains in the, now, open port.