Cracked block or leaky manifold?

[westmich]

I love this forum, this is my first post. I have a 1997 Mercruiser 3.0 Alpha I/O. Runs like a top, except this spring I have water leaking hard into the bilge area from a very narrow valley between the top of the block (port side) and what I think is a manifold (the exhaust manifold elbow comes off the rear top of this peice--it runs the length of the block, roughly, and is about 5-6 inches wide).

I am getting no water into the oil that I can tell (dip stick still oil-colored, not milky at all). I have read several posts about using JB Weld on an external crack but I cannot get to the location to prep the area or even see the "crack", if that is what it is, because it is at the very depths of that valley. Since it is coming from the place where the supposed manifold meets the block, I am wondering if it could also be a blown seal between them.

Looking for most likely diagnosis and suggestions for repair. Boat only worth about 6k and repair quoted for new enging block and labor is 4k. Can't see doing that. Any ideas are appreciated. Thanks.

 

[mkast]

Re: Cracked block or leaky manifold?

Remove the exhaust manifold, check manifold for leaks.

 

[1980Galaxy]

Re: Cracked block or leaky manifold?

cant help you diagnose it, but i had a cracked block in mine this year and had to replace the engine. i got a used one for $100 and i am friends with a mechanic that is doing the work for me for almost nothing. i really lucked out on this one but if worse comes to worse just keep your eyes open for a great deal like that. trust me, they are out there. no need to be spending $4k to repair a $6k boat

 

[westmich]

Re: Cracked block or leaky manifold?

Remove the exhaust manifold, check manifold for leaks.

Mkast, thanks for reply. Is the exhaust manifold just the elbow or is it the entire rectangular housing attached to the block that the elbow attaches to?

I haven't got my hands on a manual yet. Thank you.

 

[westmich]

Re: Cracked block or leaky manifold?

Go to the Audlts Only post, READ the instructions on how to download, and get yourself the correct manual. It will save you untold amounts of money and grief.

I did that originally, but the links are dead from the table of contents in the online manual's link. Currently looking for a manual somewhere. Thanks.