Yanmar sudden oil leak

[jwilson]

After about an hours running found the 3YM30 engine had lost about a pint of oil - and in the under-engine tray was this in the bottom of the substantial puddle of leaked oil - http://www.yachtsnet.co.uk/yanmar-3ym30-part-oil-leak.jpg

Engine oil now at very bottom of dipstick. No obvious signs of leakage at front/top of engine. Have not yet looked at back as that would have meant removing nice clean bunk cushions with (by then) very oily hands. Will return tomorrow with more kitchen roll etc.

In the meantime anyone know what it is and where it came from? I've just been through the service manual and can't find anything like it.....

 

[andrewAB]

After about an hours running found the 3YM30 engine had lost about a pint of oil - and in the under-engine tray was this in the bottom of the substantial puddle of leaked oil - http://www.yachtsnet.co.uk/yanmar-3ym30-part-oil-leak.jpg

Engine oil now at very bottom of dipstick. No obvious signs of leakage at front/top of engine. Have not yet looked at back as that would have meant removing nice clean bunk cushions with (by then) very oily hands. Will return tomorrow with more kitchen roll etc.

In the meantime anyone know what it is and where it came from? I've just been through the service manual and can't find anything like it.....

There is an alternate dipstick entry just near the oil filter. Mine came loose and I found the plug and oil in the bilge under the engine.

 

[jwilson]

There is an alternate dipstick entry just near the oil filter. Mine came loose and I found the plug and oil in the bilge under the engine.

Thanks: will look first thing tomorrow, when I return with more cleaning stuff. That makes sense: the rubber collar looks like a seal for an unused dipstick tube.

 

[Tranona]

Sounds like that is access for a tube to extract the oils to avoid using the dip stick tube. Have similar on my Volvo 2030. It is above the level of the oil in the sump but if the plug is not in guess oil might get blown out - would be messy though.

 

[jwilson]

Have now spoken to the Yanmar agent's engineer who confirms the plug is for an alternative dipstick hole: he says he has never heard of one coming out, and that he always uses the normal frontish dipstick hole to extract oil. As Andrew from earlier post has had exactly the same thing happen and it is potentially disastrous I am going to try to either wire the plug in place, or secure it with cable ties.

I lost over a pint of oil in about an hours running, that took oil to just below the dipstick bottom mark. A longer run could have done damage to the engine. Off to the boat shortly with lots of cleanup stuff......

 

[Jock89]

Had a similiar problem with my Volvo Penta D2-40. What it was, was the oil-extraction pipe that's located next to the oil-filter. This comes out & up from the sump & has a tight-fitting rubber cap on the top end. If this splits then the warm/hot (slightly pressurised) oil can be pushed up this short pipe & drip into the under-engine tray. The rubber caps cost less than 20.p each so a few spares are worth having on board.
HTH

 

[jwilson]

Had a similiar problem with my Volvo Penta D2-40. What it was, was the oil-extraction pipe that's located next to the oil-filter. This comes out & up from the sump & has a tight-fitting rubber cap on the top end. If this splits then the warm/hot (slightly pressurised) oil can be pushed up this short pipe & drip into the under-engine tray. The rubber caps cost less than 20.p each so a few spares are worth having on board.
HTH

Certainly similar, but the Yanmar YMs don't have a pipe, just basically a hole in the block just above the sump, so much more oil sprays out if the plug pops out.

 

[bernk]

Have now spoken to the Yanmar agent's engineer who confirms the plug is for an alternative dipstick hole: he says he has never heard of one coming out, and that he always uses the normal frontish dipstick hole to extract oil. As Andrew from earlier post has had exactly the same thing happen and it is potentially disastrous I am going to try to either wire the plug in place, or secure it with cable ties.

I lost over a pint of oil in about an hours running, that took oil to just below the dipstick bottom mark. A longer run could have done damage to the engine. Off to the boat shortly with lots of cleanup stuff......

Hi J. Did you figure out the cause of the issue in the end? I’m on a charter boat right now (my first one) and have experienced the exact same situation you described. Motored for a couple hours total, checked the engine last night and to my horror found the tray under it full of oil and that plug swimming in it. Waiting for the charter base to open so I can give them a call, but gathering as much info as I can in the meantime.

I find it surprising the engineer you spoke with had never heard of one of these plugs coming out…

 

[jwilson]

It does seem to happen occasionally to a few people: obviously not enough to have Yanmar do anything about it. I used some Monel wire to hold the side plug permanently in place, wired down to a handy bolt on the side of the sump. Cannot happen again now.