J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment More Engine Issues

We've had a fairly successful season with #56, newly named Canis Minor, long cruise from Portland to Penobscot Bay, wednesday night racing and plenty of casco bay cruising. But it has been a particularly bad year for our old Yanmar! After fixing her injectors early this year I have now identified an oil leak! The first indicators were a sludgy bilge and after going over the engine a bit I identified some fresh engine oil underneath where the engine meets the transfer case. Anybody had a problem like this? Must I split the tranny from the engine and replace the gasket? Maybe theres is a more common leak source and the oil is just traveling to that local? I appreciate all the support the forum has been giving me the past two years, hopefully after wrestling with #56 for awhile longer I'll be experienced enough to help out another exhausted newbie.

Thanks,

Josh

sounds like a rear main seal, unless the oil is red, then it would be a transmission seal.

I concur with Bob. One additional potential source is the oil pipe that runs in the back of the engine, but most likely the rear main seal. Check the fluid levels in both transmission and crank case.

The rear seal can be replaced by removing the transmission (you'll need to support the rear of the engine). The prop shaft coupling will need to be disconnected and shaft slid back about 3 inches to get the transmission out.

Remove the damper plate and unbolt the flywheel to remove it, You should be able to pry out the old rear main seal and replace it in place.

Download the Yanmar service manual in the main menu on this site under "info" then "Diesel Engine Maintenance"

ps - I believe you have hull number 54 not 56

beautiful, I figured as much. I bought the boat to become a better sailor and instead I'm turning into quite the diesel mechanic. Engine should be fine to run so long as i check the oil regularly and keep cleaning out the bilge yes? Thanks guys

yes - that should work, but you really want to replace the leaking seal when you can in the off season. Leaks have a tendency to get bigger, not smaller.