Yanmar 2qm20 Oil from Head - What Could Cause This

[charliehows]

2qm20, running pretty well but i notice a couple of places where there is a bit of oily stuff running down from what seems to be the head to block connection area. Im a little bit concerned that it is a sign of the head gasket being a bit...tired, although compression is fine and there are really no probs with the way the engine is running. Ive put it under 'if it aint broke dont fix it' so far but i thought id see what the wise heads on this forum think ( i prefer to fix things before they break...)

[TheOffice]

Have you done a compression test or does it just seem to be OK? Sounds like a head gasket to me too. Don't know what else it could be.

[bobconnie]

Are you sure it's not coming from the Valve cover ?? it would be part water if the head gasket is leaking !! or some compession. maybe wipe it off and look to see WHERE it's coming from ?? at least thats where I would start !! just my 2 cents

[DeepFrz]

Sounds to me that its most likely coming from the valve cover. Sometimes it can hit the block and run along the block/head seam before it runs down the block.

[charliehows]

yeah valve cover would be good - i'll do a bit more of a forensic on it.

[karl halozan]

You may want to check the external oil line which runs from the head to the block. This oil line or the fittings may have developed a leak.

[charliehows]

Originally Posted by karl halozan

You may want to check the external oil line which runs from the head to the block. This oil line or the fittings may have developed a leak.

no its quite specific - there are 3 places where a little trickle has been running down from the join area between head and block - one each side about two inches from the front of the eng. and one further back on the inlet side - im curious whether other 2qm owners have seen something similiar. My current best guess is some kind of osmotic pump effect - even though comp. is good, pressure is so high in these engines im thinking theres enough pressure to concentrate a bit of oil out of the diesel and its working its way out - sound wacky?

[Nemo55]

Could it be excess gasket sealant just liquifying? when you say a trickle, is it just enough to notice,or an actual oil run?
If you have had recent work done to the engine, or had the engine degreased it could be left over from that..

[charliehows]

no recent head work. i painted the engine a while ago which is when i noticed it, i clean it every so often, its barely a trickle, i just cant figure what it is - couldnt be gasket sealant, doubt if the heads ever been off the thing in 30 years. every time I start thinking I know a bit about engines...