Exhaust coming from breather tube & Dip Stick?

gt14 · May 6, 2006

I have a 2 cylinder diesel YM146 Yanmar. I have exhaust smoke coning out of dip stick hole and the breather vent tube. Oil has also been coming out. Any ideas what could cause this?

kenmac · May 6, 2006

I would say bad or broken ring/rings

ALABAMA_KID · May 6, 2006

I agree. Something is causing excess pressure in the crank case.

normde2001 · May 6, 2006

Male sure oil is not overfilled. If oil is dirty, change it, (seems like this only happpens with dirty oil). Make sure dipstick seal is good. Make sure muffler is not plugged up.

Bluecheck546 · May 6, 2006

This is so called "blowby" caused either, broken\colapsed compression rings. Go with thicker oil, and don't overfill. I would not worry to much about if its an older engine, if is not, I would teardown and replace rings.. Good luck.

Egon · May 7, 2006

Think it's time for a compression check and then repair/rebuild time! /forums/images/graemlins/frown.gif

Egon /forums/images/graemlins/grin.gif

gt14 · May 7, 2006

Thank you for the comments I will get heavier wt oil and do a rebuild after the season.

gt14 · May 7, 2006

When I drained the oil it had a fuel smell to it and it was very thin. I suspect fuel in the oil. What does this mean?

PILOON · May 7, 2006

Rings!

A compression check will confirm.

But on the offchance that the rings are stuck (would be generally the same symptoms) you might always try soaking the rings with some sort of penetration or cleaner solution.

Folks would often use various 'patetented' upper cylinder addetives to loosten up rings such as Whinns or Bardhall.
Other than a few dollars, there is not much to loose.
Generally they mix with the fuel and I have actually seen some good results.

Good luck!