Cat D4C blow by smoking.

[LeeB]

All the sudden I'm getting excessive smoke from my blow by tube on the Cat dozer. Rings bad?

[sawguy21]

Rings don't go out all of a sudden. You likely have a bad gasket or crank seal allowing air into the crankcase, it should be under a slight vacuum.  Pay particular attention to tappet covers and external accessories.

[moodnacreek]

How is the exhaust?  If the injectors get deposits and drip you can get blow by so bad it will be liquid and ' make' oil at the same time.  Diesels can have quite the blow by because they are high compression.

[LeeB]

Looks like it's getting more exhaust out the blowby than the exhaust. Exhaust isn't black like unburnt fuel, nor white like water. A little blue but not bad like it would be if it's burning lots of oil.

[sawguy21]

That points to a leaking head gasket or cracked liner.

[chevytaHOE5674]

Do a leak down and compression test...