Crankcase Breather Tube Extension

[jzack]

MY 94 E-7 with 913,000mi on original motor and turbo has been spitting a little more oil than usual out the breather messing up my tanks and stuff in only a couple days work. So I decided to add a 2ft. extension with a piece of radiator hose that slipped over the breather perfectly.

Now just a week later, while setting my valves, a Mack mechanic with 20+ years experience told me I should get rid of the extension because the breather should never extend beyond the oil pan. If it does, he said crankcase pressure will be off and "stuff will wear out faster" in the motor. While I tend to trust a guy with so much experience, what he said just doesn't make sense to me. IMO as long as the size of the opening of the breather tube stays the same, the length of the tube shouldn't matter, right? Anybody have an opinion and/or experience with this? Thanks.

[Lmackattack]

I see alot of guys doing this tube extension and I have never heard or seen it cause issues. My understanding is that the tube just needs to be unrestrictive.

just my .02

[Mike]

I feel the same as Trent about this tube extension. As long as it is not restricted it should be fine. I went a step further with my tube and built me a coffee can to let the oil catch inside of. It works very good and no restrictions, but I did not put the tube down into the bottom of the can. It is about four or five inches down into the can. One down side is, you have to empty the can at some point. I have no problem with that. I have no mess to cleanup neither.

Get creative

mike

[HK Trucking]

If you're getting more & more "emissions" from the breather tube, then it means your piston rings or exhaust valve guides are getting worn and allowing more pressure into the crankcase.

.

[Mike]

Amen Herb, how true a statement. I say the same as you with the mileage he told us. Most of us try the get me by approach for a while until a major problem exists. Then more parts are then needed.

Good to hear from you Herb

mike

[HK Trucking]

I hear ya Mike!

I've had a few that were getting tired and pushing more & more blow by out the pipe, then when it gets so bad you can't keep oil in it anymore there is no choice but to overhaul.

I should add that when a previously good running engine seems to suddenly get increased blow by, check the air filter & all intake ductwork to be sure there is not a leak or loose connection allowing dirt to be inhaled into the engine.

Dirt ingestion will cause rapid piston ring & cylinder liner wear, turning a good running engine into junk.

.

[jzack]

Thanks for the advice guys. I feel better about just leaving the extension on now. Keeps things cleaner. A catch can ain't a bad idea either, however I've never seen one on a big truck!

The blow-by, while making a bigger mess than usual, isn't too bigga deal YET I think. Maybe one gallon every 4,000mi. I think I was told by a Mack mechanic once to do a rebuild once your in the one gallon for every 1,200mi. range. I'm gonna keep a close eye on it now though.

Jeff