November 2002 Archives

The Boat


Here is "Te Moana", our lagoon 380 catamaran at our mooring in Pittwater.

Oil leak in MD2030

The starboard diesel engine (Volvo Penta M2030) of our brand new Lagoon 380 Catamaran has been leaking a bit of oil from the transmission area, you can see it starting to pool under the air hose:


Here is the source of the leak. If anyone has any constructive suggestion, I'd like to hear from you!

The oil is seeping out of the threaded hole which has no apparent purpose (probably used in some other configuration of the engine).

[later] the problem has been solved (see comments)



Hi there! Don't feel bad about trying to find about the heavy iron chunk in the lower bowels of your boat. Engines are a lot like opinions-everyone has one (or almost everyone).
My name is Ron Bailey, and I'm building a CC44 John Marples trimaran. I'm not a marine mechanic but I have rebuilt or overhauled literally dozens of engines, and maybe my two cents worths will help.
1. The fluid leaking is transmission fluid, so the problem must need be in the transmission itself.
2. The area of the leak does not house any parts that are bathed in transmission fluid. That particular area of the engine bell housing connects the engine block to the transmission itself and covers the flywheel.
3. A leak between the bell housing and the transmission probably is the main transmission seal on the output shaft.
4. Check your owner's manual or a parts catalog and see if they give a diagram showing the specifics of the transmission shaft seal at that point.I believe that this is where you will find your leak.
Now for the bad news-getting to the seal will probably entail separating the engine from the transmission to get access to the part. This is a difficult and time consuming repair as it is most likely in the exact middle of your engine.
As a -very-temporary fix you might try some transmission seal. It has several different chemicals which help the seals swell up and stop the leak. I personally don't have much faith in them, but it's a simple, cheap and realtively harmless thing to try. Good luck

When our Lagoon 37 was brand new, she developed a leak and TPI (builder) paid for repair which required engine removal. No problems since, 8 years and 12000 miles. Good luck.

Thanks for all your comments, on the multihull list as well as here.

Unfortunately, the most likely cause appears to be a bubble or crack in the casting which was undetected during manufature. I'm still waiting (over a month now) on a Volvo mechanic to have a look at it.

Actually, when the engine was finally serviced in early December, the mechanic convinced me that the leak was actually liquified grease. The cause was probably the use of an excess amount of grease when the transmission was mounted on the engine. As you can see in the photograph it is the hole on the side of the bell housing which shows the "drip". He put plugs in the holes and the engine is running fine three months and 60 running hours later.