Yanmar 2GM20F oil leak

AllanG

AllanG

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My Yanmar 2GM20F (320 hours) has recently developed a very slight oil leak, which appears to be coming from the sump gasket, or around that forward area.

I have checked the sump bolts, which were all tight.

Has anyone experienced a leaking sump gasket when all the sump bolts are tight? Is the sump gasket easy to renew?

I have checked the crankshaft seal........no leakage.

Any other suggestions from where the oil may be coming from?

Does this engine have a crankcase breather?

Many thanks,

Allan
 
Its worth checking the oil feed pipe to the rear of the engine.
I assumed my crank shaft seal had gone as i had a few drips that the source cound not be traced, but once again thanks to the forum a strip down was averted.
 
If you have checked the obvious - dip stick in hole, oil filter loose etc.... then it is more than likely the timing cover gasket has split. This is a common problem of the Yanmar 2GM20. but not one that Yanmar will hold their hands up to poorly designed gasket.

Symptoms - The oil leak, if it is this problem should be eminating from the bottom of the timing cover slightly to the port side as you look at the front of the engine.... it may not be large to begin with just a drip or two but when this occured on my engine it was total loss of lubricant and fortunately I had enough additional supplies of oil to limp home.

I repaired this myself so have gained the knowledge to fix this .... PM me if you want additional information.

PS beware the Yanmar manual is confusing and doesn't necessarily give you the information you need for the freshwater cooled version.

PPS as you will need to strip the engine of most of the anciliary parts it is a perfect opportunity to complete a service on the engine.

PPS parts including service bits were about £60 Took me a weekend working blind with a manual that wasn't helpful - but allow around a day of work time in total
 
Have a look at the bottom of the timing gear cover, right at the front of the engine. Any sign of oil at the bottom of this means the gasket is weaping. If this is the case and the leak is very minor, it can be cured by getting the joint area with the block very clean and degreased and applying appropriate sealer (Thiokol do suitable products: http://www.polyspec.com/technologies/THIOKOL.htm ) externally over the joint. Done properly it will probaly be more reliable than replacing the gasket and a lot less hassle. The same process can be used for any small leak at an engine joint that is unlikley to be disturbed for years.
 
[ QUOTE ]
"PS beware the Yanmar manual is confusing and doesn't necessarily give you the information you need for the freshwater cooled version."

[/ QUOTE ]

How right you are. I'm still not certain that my 2GM20F doesn't have an anode hidden away somewhere on the engine. I've asked all sorts of people and looked at internet resources, and get confusing answers (some say yes, others no).
 
The Yanmar 2GM20F does not need an anode as all partsin the cooling system are common.As for the 2GM20 raw water engine the anode is fitted on the plate at the rear of the cylinder block.
My engine had a leak at the rear crankshaft which turned out to be the main bearing housing to the block which had the rubber `O` ring nipped and this must have happened on assembly in Japan.
I fitted a remote reading thermometer pocket on the rear plate in lieu of the anode.
 
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