is there other reasons for blowby besides worn motor? i have a fresh motor and noticed i have slight blow by coming from my oil filler and blowby tube? thx ahead of times Hop

 

there should always be a little bit of blowby not an excessive amount though. the motor doesnt necessarily have to be bad though. it could just be needing some new valve stems or something along those lines

 

Blowby is relatively typical in diesels, moreso in cummins. Doesn't mean they are bad motors, it's just one of their characteristics (just like new hondas consume oil from the factory). Typically they start puffing at around 250k miles.

It could be a leak in your air pump that causes it, valve stems, or excessive amounts of oil in the crank case being spattered out.

 

THX the head was gone thru too,i thought i heard something about the turbo line causing back pressure to the crank case which cause blowby or somin like that anyone heard of that?thx again Hop Sing

 

Turbo line??

 

i wouldnt worry unless it is really excessive. cant a vacume leak cause extra blowby or somethin like that?

 

How do you know if its excessive or not? Mine has 180,000, and theres some from the tube... I'm worried now!

 

have you been around lots of diesels in your life? they will all have blowby but some just really puke it. i don't know how to describe what is a lot or a little without showing you so mabey somebody else can help with this.

 

if you overhaul one they usually will have blowby until you get the motor working pretty hard and the rings seat. had a buddy with a pete that fresh overhauled it and it used a gallon a week until he quit babying it around. uses less than a half gallon in 10,000 miles now

 

Ya thats why I said check the vacuum pump

There is actually a way to check; look online. You run tubing to the rear of the truck with water in it and you can tell how many inches of water are pushed. But how thick is the smoke? Is the smoke constant or does it puff with the motor chugging?

Truth. All diesels have blowby typically

damn a gallon a week until break-in? Thats nuts.