Yanmar3GM30

[Fr J Hackett]

It looks like I have an oil leak on the crankshaft oilseal at the output side, has anyone changed one of these, is there a decent diagram in the workshop manual before I purchase one. I guess that its relativly straight foreward once the gearbox and housing plate are split from the engine block, prise out the old and press in the new, I am hoping to do it insitu as I have reasonable access to the back of the engine and gearbox. Words of wisdom and advice please.

 

[Honey]

Suggest that you try the forum at www.yanmarhelp.com.
The manual (genuine) only contains ½ a page while another (downloaded) says "take it to a dealer". Let me know if you want a scan of the ½ page.

 

[charles_reed]

If you've a seal oil-leak, first check the breather. Hopefully it's blocked and clearing it will resolve the problem.

If not, replacing the oil-seal is wasted effort - you'll have to strip and re-bore the motor. If you do that you might as well rebuild the motor. The rear oil-seal is wear-proof.

If you do that it'll be more cost effective, given Barrus's spares prices and even if you do the strip and re-assemble, to re-engine.

I've just been through the exercise.

 

[Rick]

I'd be astounded if a leaking rear seal was an indication a rebore was required!

 

[Stemar]

Probably not a rebore, but new main bearings may be needed.

IMHO, it all depends on how hard it is to change the seal. If it's straightforward, it's worth a try, but if you've got to get the engine out and take it apart, then I'd be tempted to give it the full bottom end job, 'cos doing all that work to find you should have done a bit more while you had it apart is one definition of a really bad day!

If compression is good, I'd leave the top end apart from lapping the valves and testing the injectors