Mystery blow-by leak

[RHulette]

I've got my blow-by pipe routed to the back of the truck and it works well. I swear I saw a little blow-by vapor the the other day while waiting at a light and then yesterday I caught a whiff of blow-by as I came around the front of the truck. I can't figure out where it could be coming from.

Any ideas? No leaks anywhere that I can see. With the engine idling, the fan blows away any chance of tracing this leak.

Thanks,
Randy

 

[RollOver_Pete]

Um....
blow by would likely be coming from your blow-by pipe.

 

[DavidC]

Did you try gas x. Couldn't help myself. Have you tried the tea kettle test, turn the oil fill cap over, place it over the fill hole while the engine is running and see if it bounces around indicating pressure in the crank case.

 

[BoeingDiesel]

In addition to the tea kettle pop test check your vacuum system starting at the pump. I don't know about your truck but the dead giveaway on my '99 with a vacuum leak was the symptom you're describing.