This answers the question from the post about high oil consumption when the breather tube was crimped.
The check valve in the separator return line must have failed and the pressure in the crankcase combined with the vacuum in the intake sucked the oil into the combustion chambers.

It does leave the question as to why the engine did not shut off if the breather was crimped. Could it be that enough oil was escaping via the return tube that the pressure never got high enough to activate the shut-off?

Anyone ever check the check valve in their engine?

Is this an argument for a pressure relief valve on our engines like is found on hot water heaters?

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13