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O32 · 09-07-2018, 16:36

In another post, I talked about a cylinder head leak that I have. Today while cleaning off the exterior of the engine, I noticed oil around the crankcase sump joint.

I also checked the oil level. It is about 3/16" above high mark. I must have overfilled. Manual says it takes 2.5L. I put in 2L, but of course some oil is always left in sump.

Questions that come to mind:

1. Would high oil level overpressure crankcase & cause oil to blow out of sump joint and maybe rear seal?

2. Will lowering oil level correct overpressure?

3. Has anyone attempted sump removal without pulling engine? There is 2 or 3 inches clearance, but rear bolts are probably hard to reach!

Anyone been down this road that can offer some words of wisdom?

RaymondR · 10-07-2018, 00:10

3/16" overfill should not cause any problems.

Doubt if lowering the oil level would lower the over pressure. Some Yanmar engines have a small hose between the tappet cover and the air intake to direct crank case vapors into the air intake rather than vent them into the engine compartment. If you are seeing over pressure it is more likely that this conduit is blocked somewhere than it being from oil over-fill.

Removing the sump with the engine in the boat will probably prove both messy and difficult. Try to check whether the sump bolts are all tight first and you should get an idea of how difficult it would be.

jimbunyard · 10-07-2018, 02:04

Above is good advice. Check that the breather, whether it vents to atmosphere or the intake, is clear; if not it can cause the natural low crankcase pressure to make oil seep through seals and gaskets it normally would not. Also, an overly full crankcase can cause seepage just from the greater amount of oil being thrown around inside, especially if any gaskets or seals are a little substandard...

The correct oil level can be idiosyncratic for different applications of the same engine. Some engines run more cleanly with a slightly different level than is indicated by the 'correct' level shown on the dipstick; the actual optimum level can only be determined by experience, within reason of course. If your manual says capacity is 2.5 liters, don't think 1.5 is enough. At least 2 would likely be adequate though, and 2.25 better, and if that kept the oil in the engine that's where I would run it.

If you tighten the pan bolts, remember that the important thing is uniform tension applied evenly around the flange. You're not torqueing a head; about 7-10 ft. lbs. is all that is required initially, but if the gasket is already compressed, you might have to go up to 12-15 or so to get it to seal, for 6mm, 8.8 bolts that is...

O32 · 10-07-2018, 07:01

Thanks for input.

On this engine, there is no valve cover vent. But there is one from front cover to the air intake. I have been hesitant to remove old hose because it still has original paint on it and is no doubt brittle. Did find part description. Looks like 9mm ID/12.5mm OD. I will make sure it is not blocked.

I will lower the level a bit, clean the engine, boat in area and get a better idea where leak is coming from. It's not much. but wasn't there last season

Will see if I can get at all the sump bolts, before re-torquing them.

Thanks again

Compass790 · 10-07-2018, 11:17

You could just replace that breather hose with the appropriate size fuel hose. Dont give yanmar the chance to ream you with their over-priced parts pricing.Otherwise what the others said. Good luck

O32 · 12-07-2018, 05:54

Quote:

Originally Posted by O32

On this engine, there is no valve cover vent. But there is one from front cover to the air intake. I have been hesitant to remove old hose because it still has original paint on it and is no doubt brittle.

I was able to get the hose off without damage. It was clean. Check intake port, and it just had a thin film of oil, so soot. Ran a wire through breather ports and they were clear.

Quote:

I will lower the level a bit, clean the engine, boat in area and get a better idea where leak is coming from. It's not much. but wasn't there last season

Will see if I can get at all the sump bolts, before re-torquing them.

Sucked out excess oil. Was able to get at the sump bolts. Using short ratchet handle, was able to tighten them a little. But only 0-1/8 turn.

Now back to head removal!

RaymondR · 12-07-2018, 20:45

Not sure about the QM series but the GM series has small steel external oil lines towards and around the back of the engine which tend to rust and get pin holes in them, might be worth checking for leaks there before you start on the head.

O32 · 13-07-2018, 05:19

Quote:

Originally Posted by RaymondR

Not sure about the QM series but the GM series has small steel external oil lines towards and around the back of the engine which tend to rust and get pin holes in them, might be worth checking for leaks there before you start on the head.

On the 2QM15, I only see one external oil line and it is a short jumper on front of engine. The feed to rockers is internal, I believe.

The head is seeping water at gasket, so that removing head and installing new gasket will be first step.

circa1971la · 23-09-2023, 08:45

I have a similar issue with my Yanmar2YM15 I’ve not been able to resolve. I posted this on April 9 here and got some suggestions that haven’t helped yet and hoping you all might be able to help after reading this thread here.

I had the boat hauled out and engine service /oil changed by a highly reputable mechanic here. Thereafter oil leaked in a square patterns dripping from the right side (facing) of the engine after heavy use and sailing.

The mechanic came back and checked it and said it was “residual oil on the engine that was not cleaned efficiently during the last service”. He cleaned the engine and start/ran the engine at slip “to temperature “ and did not notate any further leaks or drips.

Problem continues again after hours of motoring and sailing. Then they said it was “probable residual oil on the gear case, it is very difficult to get residual oil off the gear case due to the material it is casted in”

I have few to no mechanic skills but it appears to possibly be leaking from the oil sump seal.

Question-

this never happened before I had my engine services so is it possible they overfilled it with oil?

Does this sump and seal typically get removed during a service ?

Any advise is much appreciated!!

PS please see my post 4/9/23 titled “ Yanmar 2YM15 Oil leak Pattern- Need advice please”

deblen · 23-09-2023, 10:13

Workshop Manual.
https://sbo.sailboatowners.com/downl...n_34429454.pdf

circa1971la · 23-09-2023, 11:57

Thank you so much. I don’t see a reply here just a link. Does this sound to you like it’s just the gasket or could this occur if they put too much oil in?.