Posted: November 16 2010 at 08:51 | IP Logged

We have a 1984 381 Catalina with 454 Mercruiser engines. The stb engine seems to be throwing oil about the bell housing area (if it was a car, I suspect we would be having clutch problems about now). Does anyone know if the rear main seal can be replaced without removing the engine. All advice and/or assistance gratefully accepted

Tom

Posted: November 16 2010 at 15:34 | IP Logged

Tom - sorry to be the bearer of bad news but the answer is no.  I had a 1985 381 and those year model engines had two piece rear seals.  There is not enough room to jack up the engine far enough to drop the oil pan enough to get this done.  You'll have to pull up the flooring and build an A-frame to lift the engine high enough to get to everything.

If you decide to go this route, re-install a one-piece oil pan gasket.  Easier to deal with than the two-piece.

Now, all this being said; just how bad is your leak?  Let's say you run the boat on a trip of 6 hours length.  How much oil are you using?

I have a friend who put new engines in his boat a few years ago and the seals have leaked since day-one!  He keeps a clean, neat engine room and is a top-flight engine mechanic but simply will not deal with changing the seals (and his are the one piece and can be changed without pulling the engine).  He simply keeps absorbent oil pads under both engines and changes when he feels they are ready to be changed.

I have a leaking oil seal in my DD6V92 diesel engine in my 500 Connie.  I do the same thing with the pads. A mechanic told me he might as well overhaul the engine as what it would cost me to put a rear seal in the thing!

I guess you know where I'm going.  If it ain't too bad, put some pads under the offender and add oil as necessary.

Hope I've been of some help.

Emory

Posted: November 16 2010 at 15:39 | IP Logged

Tom - do you ever visit the Catallina forum?  I know it seems like they're a bunch of 250/80/94 nuts there, but they have a couple of 381 lurkers and I'm sure they'd welcome you with open arms.  They're a good bunch of Catalina owners who have offered each other some great advice.  A lot of which is transferable to the 381 Cat.  BTW - I have owned a 294 and a 381 and now a 500 Connie.  Sure miss my 381!

Emory

Posted: November 17 2010 at 01:30 | IP Logged

Hello Captain Emory

Thank you for your response(s) on my oil seal question. I was not surprised. Looking at the thing, it did not seem possible to replace that seal in place (for me anyway), but we live in hope. The oil usage rate would probably be considered excessive in a car, but maybe not so in a boat if you are looking at a 4 figure repair bill. We ran the boat about 110 miles Friday in about 5 hours and used about 3/4 of a quart of oil. I have observed that the engine seems to use less oil if I am not is such a hurry, and typically I am not in a big hurry so I think for now I will probably take the oil absorbant cloths under the engine option and add wiping down the spray area to my work list. Even at todays prices, I can buy a lot of oil for $1,000.00.

Regarding the Catalina forum, I thought I was there. I had gotten some good advice from "DiverYates" on an engine cooling problem on what is now my old boat (we sold it last month). At any rate, now you know why my handle is "Tomconfusion".