Yanmar 3GM30 Oil Leak

[sailorchic34]

Originally Posted by Sailorman Ed

Sailorchic-my steel line measures .188 dia. Do I want 1/4" OD (1/8" nominal) or 1/8" OD? Sorry to be so anal....Ed (with a 2GM20)

Tubing size is always the exterior dimension. Pipe size is interior. So copper tube would be 1/8" OD or .125"

Oops I stand corrected. I used 3/16" tubing, which is .188" dia. ( I checked my spare bit of tubing just now.) Darn blonde moments...

[Sailorman Ed]

I got my new copper line and it went in easily. Thought some folks might like to see what it looks like. Last picture is with the starter removed. I got a package of copper washers at the auto parts store, 3 sizes in the package for about $5. No more oil leak.

[don da mon]

Hi, I went to replace this oil pipe on a 3gm30.
I removed the fuel pump as it was corroded from the saltwater leaking on it from the mixing elbow.
One of the banjo bolts has a MUCH smaller hole cross drilled, where does it go??
The bolts got moved around due to a wake where the moat was moored.
Any help?

[rbyham]

About a month ago I ordered and installed the new external oil line due to seeing a small oil leak on rear of the 3qm30 engine right where line follows head/block joint. On testing it looked good in terms of stopping the leak.

Unfortunately it seems the test needed to run longer because I was checking engine over the other day and noticed oil leak back in same spot. So evidently while my external oil line needed changing as it was deeply rusted, the leak comes from elsewhere. I am now suspecting the head to block joint and wondering if there is any approach to this prior to a new head gasket?

I have no experience tightening head bolts but I am wondering if this vintage 1978 might benefit from taking valve cover off and making sure head bolts are in spec. I have a torque wrench and the manual which describes tightening order and torque spec but I was wishing to hear from someone with more experience in terms of the likelihood i could get a fix by torquing the head bolts or if this is a bite the bullet and change head gasket situation?

[sailorchic34]

Originally Posted by don da mon

Hi, I went to replace this oil pipe on a 3gm30.
I removed the fuel pump as it was corroded from the saltwater leaking on it from the mixing elbow.
One of the banjo bolts has a MUCH smaller hole cross drilled, where does it go??
The bolts got moved around due to a wake where the moat was moored.
Any help?

If its for the fuel pump, the small hole banjo bolt goes on the discharge side of the pump.

[Sailorman Ed]

Rbyham,
I did the same as you but the leak turned out to be the main oil seal.
Disconnected from the saildrive, removed the flywheel and replace the seal.
No more leak.
I found it by placing the white oil soak pads in different places until I was sure it was coming from the bellhousing. Suggest you try the same.
Ed