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Full Version: Blowby/high crankcase pressure
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Changed 7th injector, updated fuel line and exhaust gas pressure sensor on Cummins isx cm871. Still wouldn’t get hot enough to regen. Changed turbo as it was over spinning and it now regens. However, have high crankcase pressure. Will attach video. Any ideas?

https://www.dropbox.com/s/klqie40i1nc19t...M.mov?dl=0
Yea, your crankcase filter is probably plugged up and possibly has never been changed. You can drill holes in the original one or buy the maintenance free one from cummins.

https://rawze.com/forums/showthread.php?tid=65

If you have a ton of blowby it might be time for an inframe. Or possibly your turbo is pushing pressure into the crankcase through it's oil return line.
You may have mentioned in another post, but what kind of hrs/mileage is on this engine? And yes, Tree is correct on the crankcase filter. Check it...many people have no clue it can and should be replaced (preferably w/ a maintenance free one).
(03-05-2023 )SquareOne Wrote: [ -> ]You may have mentioned in another post, but what kind of hrs/mileage is on this engine? And yes, Tree is correct on the crankcase filter. Check it...many people have no clue it can and should be replaced (preferably w/ a maintenance free one).

There is a little over 300,000km (done in late 2018 at Kenworth Amos Quebec) since engine swap and rebuild. The crankcase filter was recently replaced.
When you say "done" are you saying it's been rebuilt? You said "engine swap" are you saying you had a different engine put in the truck and then rebuilt? Doesn't seem like you gave us all the information.
What engine ESN was in it before and what ESN engine is in it now? What's the serial number of the aftertreatment system?
There is a ton of the info in her first post. All ecm stuff was verified and I think they even flashed for the updated dpfs. Truck is still mandated.
Id disable the crankcase breather all together, these engines need to breath a bit
(03-08-2023 )windowrattler Wrote: [ -> ]There is a ton of the info in her first post. All ecm stuff was verified and I think they even flashed for the updated dpfs. Truck is still mandated.

Oh ok I remember this story now. That's an awful lot of blowby for a rebuilt engine.
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