Yanmar 2GM20F Oil pan leaks

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Oct 29, 2005
2,362
Hunter Marine 326 303 Singapore
I notice oil drips from under my 2GM20F even when engine hasn't run for a week or two. On closer inspection (with a small mirror) I see oil forming at the oil pan gasket right under the engine. There was no oil drips/oil stain from higher up the engine body. Question is can I remove the oil pan and change the gasket as is without hoisting the engine out? I think I can access all the 16 or 17 bolts (10mm AF ?) underneath.
Meantime, I've retighten all the oil pan bolts (some weren't very tight) and will check it again coming weekend to see if it is still leaking.
 
May 11, 2005
3,431
Seidelman S37 Slidell, La.
I removed mine

I removed mine on a 3GM to install a drain plug. Not a problem. If you pull it to replace the gasket, I would strongly advise drilling and tapping it for a drain plug. Makes oil changes much easier and cleaner.
 
Oct 29, 2005
2,362
Hunter Marine 326 303 Singapore
Nice N Easy, thanks for the info. Sounds nice n easy enough :D Any particular place to drill the pan for a drain plug? Towards the stern end I suppose. Is there a low flat spot thick enough? :dance:
 
Dec 1, 1999
2,391
Hunter 28.5 Chesapeake Bay
I think I had a similar leak on my 2GM20F last year. I did tighten all the oil pan bolts (I think with a 11mm socket). No leak since. Keep us posted.
 
Apr 19, 2011
456
Hunter 31 Seattle
I recently had a similar issue and found it to be a loose oil dipstick! When the boat was heeled over a little oil would dribble out onto the case but when the boat was back at the dock or level it slowly ran down and collected on bottom of case. I replaced the dipstick and cleaned it up real good and havent noticed any more oil.
 
May 11, 2005
3,431
Seidelman S37 Slidell, La.
Drain plug

On the 3GM there are some recessed flat areas that are just about perfect. And at the very rear of the pan. The way I rigged mine was. Drill and tap, and put in a brass street ell. Then a brass adapter to hose fitting. Enough hose to reach close to the front of the pan, and then a ball valve. Then a longer piece of hose from the ball valve. This hose is fairly long, and I hang it higher than the level of oil in the pan, so just in case the valve would seep a little, it still stays in the hose. Works like a champ, and makes oil changes much easier.
 
Dec 19, 2006
5,832
Hunter 36 Punta Gorda
Leak

My 3YM in my 07 H-36 is also leaking and not much room to check the drain pan bolts and so have not to find where or what is leaking,
But now will check the dip stick plug and see if that is the problem,I did think about adding a drain plug but not much room to work on removing the pan and than adding a drain plug so much work not easy and what if making more trouble with some place else to leak or even worse if plug loosens up while motoring some day and the oil all runs out and blow the engine,some one with 30' catalina had the plug fall off and blew the engine up.
I am just saying really sounds like a good idea but why did Yanmar not add a drain plug,when I worked in trucking for some 35 years I saw 2 engines blow up and 1 while I was driving and it was too late when I heard the warning buzzer because the drain plug fell out from diesel vibration.
For me using the ddipstick pump out is fine and one thing less to worry about while motoring,I don't have oil or temp gauge just warning buzzer just my 2 cents.
Nick
 
May 11, 2005
3,431
Seidelman S37 Slidell, La.
Seadaddler

The way I did mine was first I used a NPT thread, which I tightened firnly. With the hose on it, it can't turn much at all. No more than 1/4 turn. And I check it regularly. Been on there a couple of years now, and not problem what so ever. If you have enough room to get the pan off, you will have clearance for a street ell. You only need less than an inch.
 
Oct 29, 2005
2,362
Hunter Marine 326 303 Singapore
Since tightening the pan bolts last weekend, i checked yesterday, it still leaks. Looks like i need to take out the pan for gasket replacement. Will consider the npt elbow fitting. Thanks.
 

Blitz

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Jul 10, 2007
708
Seidelmann 34 Atlantic Highlands, NJ
Take your time, wipe it all clean (the oil pan, bolts and transmision housing). Take a mirror to look at it to be sure. Come back in a week and look closely again with mirror with plenty of light. What you are checking is to be sure it's not coming out of the transmission. There is a small rectangular slot in the bell housing. If you do have a trail of oil from this slot it is either your rear main seal or your transmission seal. Clean oil would be from transmission side and dirty from engine.

For those who changed their pan gasket with success, please clarify if any spray tack was used. Seen it done both ways, not sure if needed or if should go on dry.
 
Oct 29, 2005
2,362
Hunter Marine 326 303 Singapore
Take your time, wipe it all clean (the oil pan, bolts and transmision housing). Take a mirror to look at it to be sure. Come back in a week and look closely again with mirror with plenty of light. What you are checking is to be sure it's not coming out of the transmission. There is a small rectangular slot in the bell housing. If you do have a trail of oil from this slot it is either your rear main seal or your transmission seal. Clean oil would be from transmission side and dirty from engine.
.....
I did just that, gave it a good clean up last weekend. Was disappointed that I'm finding oil at front end of Oil Pan and noted oil trial slightly higher up the front of engine body ...:doh:
Will have to remove the CW Pump for better view but not now. Have a trip cruising coming up. Don't want to start something I can't finish in time.
 
May 11, 2005
3,431
Seidelman S37 Slidell, La.
Blitz, long time, no see.

When I did mine, I used a small amount of sealant on the pan, mostly to keep it in place while installing. The idea of knocking the gasket out of place while getting it up under there was disturbing. Another easy way is to tie it through the bolt holes with sewing thread. But I had the sealant, and didn't have the thread. Hows you boat doing.
 
Oct 29, 2005
2,362
Hunter Marine 326 303 Singapore
Found the leak. Not from oil pan but alittle higher, front cover of engine. Cannot diy this part. Way too much engine to dismantle.
 
Apr 14, 2010
195
Jeanneau 42DS Larnaca Marina
Found the leak. Not from oil pan but alittle higher, front cover of engine. Cannot diy this part. Way too much engine to dismantle.
Check the primary fuel pump. The priming lever coming out of the pump tends to leak after a while. The back of the pump is immersed in crankcase oil since it's mechanically operated. Good luck.
 
Oct 29, 2005
2,362
Hunter Marine 326 303 Singapore
Looks like i'll have to live with this leak for now till such time i have to overhaul the engine. Leaks is not significant ...as yet. Will prob try tightening those bolts around leak area. Sigh....
 
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