oil breather smoking

[jay15]

Hi i am not sure if this forum is for diesels but i am looking for some help, and hoping that someone knows even a little bit about them.
My Yanmar 4LH-DTE has a problem, the oil breather has some smoke coming out of it, do you think this is an issue? any suggestions at all?
Thanks alot guys!

 

[Bondo]

Re: oil breather smoking

Ayuh,....

I'm not familiar with Your motor,....
But,...
That usually indicates Alot of Blow-by,... Bad Rings,..??

A Compression Test would probably tell you.....

 

[JustJason]

Re: oil breather smoking

hmmm....

when's the last time you changed the oil in the motor?
what's the oil level look like?
does the oil smell like desiel?
when was the last time you cleaned the cap?

 

[jay15]

Re: oil breather smoking

First of all, Thank you so much for the quick replies!
We haven't changed the oil in a while but the oil level is normal....

Bond-o, do you think that if the rings were bad the engine would be smoking alot and use up alot of oil?

CaptJason, I have to check if the oil smells like diesel but the air filter for the turbo-charger has oil residue on it from the breather, do you think thats normal?

note: the engine is running well otherwise.

Anymore help is warmly welcomed! thanks guys!

 

[JustJason]

Re: oil breather smoking

No its not normal.
If your oil is older, and especially if it wasn't the correct viscosity to start with, your going to have a smokey oil.

Your best bet is to change the oil/filter with what oil Yanmar spec's (I don't know this so you may have to look it up) Then clean or replace the air filter.

When you say oil breather are you talking about the fill cap? If you pop that off and flip it, does it have holes in it and look like it has a brillo pad up inside it?

 

[jay15]

Re: oil breather smoking

The oil is pretty old but it hasnt reached the amount of hours that its specs say. We are using the right viscosity oil that Yanmar recommends so i do not think that the type of oil used is the problem as the starboard engine does not do that.

When i say oil breather, i mean the open end hose that comes from the crankcase. and it is pointed directly onto the the turbo-charger air filter. Not the filler-cap. The filler cap does not have a vent.
Thanks for the help though! I will change the oil and filter and see how it goes.

 

[Bondo]

Re: oil breather smoking

Bond-o, do you think that if the rings were bad the engine would be smoking alot and use up alot of oil?

Ayuh,....

Diesels have several Rings on each piston,...
The Upper 1s are for Compression...
usually the Bottom 1 is for Oil Control....

It's quite possible the the top rings are degrated,+ yet the Oil Ring is still functioning.....

Like I said,....
A Compression Test will tell you.....

 

[Jason Councilman]

Re: oil breather smoking

Not too familiar with Yanmar, but having been around on-highway and large off-road diesels, a scuffed cylinder will give you smoke out the breather.

Bad/broken rings will do the same. Running too long on a broken ring will score/gouge the cylinder walls. Basically, you start pushing fuel/combustion gases into the crankcase.

Does the oil have a heavy fuel smell (worse than you'd expect at the hours you have on this oil change)?

 

[jay15]

Re: oil breather smoking

ahh yes Bond-o, i'm thinking i should check out the rings since you described how the diesels have multiple rings. note the engine DOES NOT smoke (only the breather does).

Jason Councilman, thanks for the input on the subject. I see what you are saying...but just to clarify things a bit here, a scuffed cylinder can make the oil breather smoke but not necessarily the engine?
I haven't checked the smell of the oil yet but if it does in-fact smell of diesel i think we know where we are going with this...

Thanks again guys! and since I'm getting alot of hints about bad ring's, i will see about a compression test!

 

[jay15]

Re: oil breather smoking

Bubba1235, the "air box" you mentioned, is on the turbocharger right? because we clean them out pretty often. Or is the "Air box" on another part of the engine?