Oil leak coming out of the breather on top of the air filter Why?

[Jobs_a_ good_ un]

Just been down to boat and cleaned up the bilge for the fortieth time and the only place any oil is coming from is the breather which is on top of the air filter it seems to be going in to the sponge of the air filter and dripping down underneath
So it doesnt look like crank case oil seal I hope, the place the leak appears is under the air filter
I had a look around the seals and there doesnt appear any leaks it looks dead clean
I cleaned all around the filter an it was pretty well saturated
but why would it keep coming out 6 mths 70 hours after it was overfilled

 

[steverow]

Checked the Turbo...?
It is possible (Ive had it on a Perkins) for oil to drip through the turbo and back into the air intake....
Just a long shot.

Steve.

 

[compie1]

Sami,

Tried boatdiesel ? you need a subscr. tho cost only $ 25 for a year and got great help on there

 

[dt1]

The only time you would get oil comming from a breather is if you have preasure in the crank case,,which means you have preasure leaking past the piston rings,,on new turbo engines they run the boost preasure so high to get the horsepower out of the engines the piston rings have to be 100%... take the oil filler cap off with the engine running and see if you can feel a preasure difference between the two engines(have a rag handy)its only my oppinion i stand to be corrected .. how much was the engine overfilled it could of dammaged an oil control ring,,

 

[duncan]

my 4LHA has a metal 'filter element' in the crankcase breather then into that pipe which is designed to feed any oil onto the air filter element where excess gets drawn into the engine and burnt off............apparantly

could you have oil trapped in the breather pipe above the filter element? worth removing the pipe / breather element?

 

[Jobs_a_ good_ un]

Thanks duncan will suggest that tommorrow to engineer

 

[Powersalt]

if you have an engineer. And he is good, then he should know better than you what to do,

 

[dt1]

how big is the breather pipe? too have held so much oil for so long ,,are there any other crankcase breathers that might be blocked

 

[Jobs_a_ good_ un]

The breather pipe must be an 1inch to the outside maybe a bit less

 

[dt1]

do you think it would of held as much oil as you have cleaned up,, and it sounds like its still coming,, just a thought have a look at both dipsticks are they marked the same and the same length,, it could be something silly like that....

 

[dt1]

how did you get on today

 

[marcusgillies]

Yanmars if oil is comming out of the breather on your yanmars normaly its becouse you have two much oil in them. idealy on those engines the iol level should be 3/4 up between the low and fill level, dont forget oil expands when hot.

 

[Jobs_a_ good_ un]

Spent about 3 hours with engineer and the only thing we could find was a pipe underneath the breather with a loose jubilee clip took off the breather etc filter cleaned them all out
reatched the loose clip etc went out for a spin and for about 20 mins thought we had solved it no leak but then upped the revs and a small leak appeared in the usual spot it may be the residue of the oil from the loose pipe which was soaked
going out again tommorrow so will let you know then
there did seem to be quite a bit less oil than usual after my blast so you never know we may have cracked it
regards
mark

 

[oldharry]

I agree with Dave Thomas that if oil is being blown out of the breather then either the sump is overfilled, or you have excess crankcase pressure. This assumes the breather system is clean and working properly - not gunged up.

ECP is caused by blowby - worn or damaged rings, a faulty turbo, or possibly a leaking head gasket. To check it, close off the breather tube, and remove the oil filler cap. Run the warm engine at fast tickover (15 - 2000 RPM) with a rag held firmly over the filler orifice for not more than 10 seconds. Release it - if there is a 'whoosh' of gas from the filler, you have ECP.

One unpleasant side effect is that if you run an engine with ECP hard for any length of time, sufficient oil can accumulate in the inlet manifold for the engine to actually start running on it. It will then race violently making horrific clattering noises even after it is switched off, and will produce enormous volumes of thick whitish smoke. If you are lucky it will then stop, and will then start and run normally, until next time you thrash it....

If you are unlucky, something breaks and you need a new engine. I ran an old Perkins with ECP for most of a season by turning the breather in to an empty oil can. The ejected oil collected in the can, and a second tube from the can to the inlet manifold sucked some (not all!) of the fumes back into the engine. A bit smelly, but effective as a stop gap! The excess oil was simply tipped back into the engine every couple of hours. Fortunately under about 2/3rds throttle there was very little discharge.

If your engineer has just cleaned out the breather, and ECP is not excessve, it will be a little while before the oil 'leak' shows up again - unless you thrash the engine hard!