Universal M25 Oil Leak from Block Plug

[texascat30]

Hello folks -

I was changing the oil on my 1985 Catalina 30's M25 and discovered I had lost a lot of oil in my bilge (cleanup in progress...). I narrowed the leak down to a small block plug next to the oil filter. It only leaks with it's running...and the leak has actually splattered significant amounts oil onto the oil filter and surrounding components. The linked photo's arrow indicates the plug that leaks, after being wiped clean.

Before I put a wrench to this, has anyone seen this before? It is a 450 hour motor that runs flawlessly. However, I may have overfilled it with oil last season (which is a different story).

Also, this will be my first post - mostly because I can always find the answer I need in older posts. So, thanks everyone - there are many silent beneficiaries of your past discussions.

Regards,
Baz

 

[31seahorse]

Hello Texascat 30,

Are you convinced that the plug is leaking? I will let others discuss that possibility, BUT I would investigate the gear case cover also. The location of the bracket that holds the alternator is on the right side of the engine as you look at it from the front (belt) side. The bolt that holds the roughly "H" shaped bracket goes through an "ear" of the gear case cover that sticks out from the engine.

If your engine is not built like that you can ignore the remainder of my post.

We were finding splattered oil in the area of the filter and on that side of the engine also. What actually happened was the "ear" cracked a chunk out of the gear case cover and the entire bracket and alternator came loose. It was not pretty!

There is an upgrade available from Diesel Direct (and probably other places) to change the mounting to a more beefy location associated with the exhaust manifold and the tank associated with it. I am not a mechanic, as you can tell from my terminology, but I was easily able to install the upgrade with the parts and instructions supplied.

If the gear case cover is damaged it will need to be removed and welded. That is a dicy project, but it is managable. We have a wonderful friend who welded the gear case cover and saved us the expense of finding and buying another to replace the original.

NOTE: In the upper left corner of your picture is where that "H" shaped bracket appears to be.

Best wishes as you investigate the leak.

 

[texascat30]

Hello there 31seahorse,

You were spot on. From my angle, I did not notice that the oil ran down into the plug fitting. I looked up on the alt bracket as you suggested, and found a hair line crack. Once I started it, sure enough, the oil was practically squirting out (pic is below).

I just found the following perhaps related thread...and thus I begin another project. I am going to need much technical (and moral) support on this one! However, I do realize that I am fortunate the alternator did not come flying off and cause more damage.

http://forums.catalina.sailboatowners.com/showthread.php?t=131499

I will likely reach out for help on repairing the gear case cover and part numbers. The first thing I need to do is sleep on this one...

Thanks for the quick diagnosis!

 

[31seahorse]

I read the other posts that you mentioned. Good information there. The repair can be done. The diagram of the replacement bracket is pretty clear. New longer studs went into the exhaust manifold to give enough length to attach the new bracket.

Again, best wishes.

Phil