I bought my gaskets directly from Cummins, and the parts guy there told me about the O-Rings, or I wouldn't have known about them.

Call up Cummins in your area, they should be able to get you the o-rings. If they don't know what you're talking about, you could always get them shipped from Cummins NW in Renton WA, where I got mine from..

I wouldn't use a generic hardware store o-ring unless you know that they are made of Viton. Regular rubber doesn't hold up to the heat and oil exposure as well.

 

Thanks!

I will order them today!..

Tx

 

Sorry I didn't reply quicker TRCM...
Yep! Like Infidel said.. The vac pump exhausts into the accessory case and that vents through the crankcase to the breather tube.
Ever since I bought my CTD, it had a pretty good plume of oil smoke issuing from the breather tube. I used to think that was normal...
This year I stumbled across a huge vacuum leak right at that little rubber coupling elbow where it pushes onto the steel nipple of the vacuum pump. The bottom of the rubber elbow had a hole sucked in it and it could NOT be seen from the top. I felt it with my finger while the engine was idling. (that vac pump can suck a serious amount of air!)
Thankfully, my engine's blowby is now a whole lot better than before!
AND it looks like my oil consumption has apparently gone down too!

Keith