My neighbors truck has noticeable smoke coming out of the breather hose. In day light cant see it at night tho in the head lights you can notice a light haze coming out of front grilland such. How much is normal , i know the case tractors at work smoke noticeable in the day light out of the breather tube and run just fine. So how much is ok on our trucks?

 

what year and how many miles are on his truck??? mods??

 

When my truck was stock, it had heavy blowby, in the winter you could see it from the drivers seat drifting up the fender wells. I had it to Cummins, worried about it the whole time I had that engine in.

Other than the blowby, the engine used no oil, had good power, good economy. On tear down the rings were fine. I don't know why, but it did that. This engine does not have any visual blowby, but does have some pressure coming out, just cannot see it.

One test that you can do is to check the vacuum pump for leaks into the crankcase. Also a vacuum leak can cause some blowby. The exhaust of the vacuum pump is into the timing case cover area. A bad leak pumps air into the engine.

 

99 3500 4x4 dually 89xxx stock. Theres some oil blow by but just some residue not enough to make drips reach the ground. It uses no noticable amount of oil between 7500 changes.

 

I have the hose extended down by the front axle. On cold mornings I get a steady puff out of it. I never noticed it during the day time or warmer weather. I just figured it was steam. The truck has never used a drop of oil between oil changes. CJ

 

yea i dont think its any thing to worry about since it doesnt use any oil. He doesnt have to add any between oil changes. but was just wondern about it, and see others did it.

 

I have a new eng in my truck. has aprox 14,000 miles so far. Ther is a small amount of blow by in my breather tube, and it uses about 2 quarts of oil in 6,000 miles pulling a moderately loaded tandem trailer at 70 to 75 mph. My eng is still breaking in though.

 

A lot of them seem to do it, I wouldn't worry too much. Mine does it some especially when cold. I think HID may be on to something with that vacuum pump thing, mine needs resealed, maybe that is part of the cuase of mine????