Oil Leak

[buddybear]

Every time I run my engine M25XPB I get a puddle of oil on top of the secondary spin on fuel filter.
I have noticed that the filter around the air intake is saturated with oil. The air breather hose is cut at an angle and lays on top of the air intake. I figure the oil is dripping from the filter around the air intake down to the top of the fuel filter. Is this normal?

Thanks,
Mark

 

[leo310]

I have an Yanmar on my 310 but it sound like your engine block is pressurize and oil is being blown up the oil breather tube. I don't know if you have a PCV valve if you do check to see if it plugged.

 

[dmax]

If by "air breather hose" you mean the crankcase ventilation hose, then that is likely your source of the oil. When the engine spins, positive air pressure develops in the crankcase and is released via the ventilation hose. Since there's oil in the crankcase, the air will generally contain some amount of oil in it. When new, there's very little. As the engine ages and the piston rings wear, there will be more oil. Lots of oil is not a good sign. From the factory, the ventilation hose just went straight down and any oil would end up in the in the engine bilge pan. Many people re-route the ventilation hose to the air intake to reduce any smell and/or oil. You can also add an oil separator to reduce the oil that goes into your engine intake. Here's a thread if you want to read more: Oil "breather" hose to Air intake

Now, is it normal? Yes, if there's isn't too much oil - a big puddle in the engine pan would be a concern but doesn't necessarily mean the end of the engine.

 

[kappykaplan]

The air breather hose is cut at an angle and lays on top of the air intake

Why not attach the air breather hose to the air intake?

 

[Stu Jackson]

Here are ways to do it ( 25 engine, but similar to yours):

Breather Hose 101 (w/ K&N Filter Pictures from Rick Allen)

K&N air filter breather hose

and Noah's: Oil "breather" hose to Air intake

and Kloeber's PDF and wiki link: Options to route crankcase breather to air intake

 

[leo310]

Just remember that a diesel engine could continue to run even with the fuel shut off if out side fuel is found. (oil intake via air intake)

 

[kappykaplan]

oil intake via air intake

It's a mist of oil, not enough to support combustion.

 

[buddybear]

It's a mist of oil, not enough to support combustion.

Thanks for all of the replies, I see that this is fairly normal, the amount of oil leak is small. I may reroute the breather line from the crankcase to another area where I can collect the residue oil.

Thanks to Everyone

 

[john2]

in older engines you can route the hose through a can or plastic bottle. both hoses on top of the bottle and exces of oil collects in the bottle the exit hose goes as normal to the air intake of engine.
John

 

[RoyS]

On my Yanmar 2QM15 that breather hose enters the intake casting after the air filter and does not contaminate the filter with oil. Regarding that oil mist: If you think your rings may be worn, try this test. Place the end of the breather hose in a glass of water while the engine is idling and observe the bubbles. You should see a slow steady stream of bubbles but without any splashing. Note this is just my own observation after I rebuilt my engine.