Small leak in cooling manifold

[bds85466]

Merc 898 I/O.

I had the engine cover off last night and I noticed what looked to be like a pinhole sized leak on the right side of my engine while running. The stream of water (taste test) was no bigger than a strand of hair, but I really think this could turn into a large problem fast as there appears to be some rust around where it's coming from. At first glance I couldn't tell if it was near a seam or if it truly was a hole. I haven't taken a good look at it in the light yet, but the water seemed to be cool at first, and then turning hotter as the engine ran -- obviously water from the cooling system? It was squirting away from the engine, onto the inside of my engine cover, not directly onto the engine. I ran the boat and watched the temp, which never ran too hot.

I'm trying to figure out what information would be helpful to bring to the forum for some advice. Tomorrow I plan on taking some pictures to communicate the exact location and condition of the hole. Is this something that can possibly be plugged/sealed? Am I looking at a much larger problem?

 

[bds85466]

Re: Small leak in cooling manifold

no doubt.

I'm no one's mechanic, but fairly inclined. Is it easy to pull this manifold off? If I had pictures it may help.

 

[Bondo]

Re: Small leak in cooling manifold

I'm trying to figure out what information would be helpful to bring to the forum for some advice.

Ayuh,... The pictures of Exactly where it's leakin' should work...

 

[bds85466]

Re: Small leak in cooling manifold

My hunch is it is near a frost plug, but I'll wait to confirm this with pics after I get the cover/seat removed. Thanks guys.

 

[bigskiohio]

Re: Small leak in cooling manifold

as long as it is a external leak wont hurt but will need fixed sometime. i have a leak from rust at plug and it has been fine for 3yrs but i am looking for a replacment. only leaks while it runs the bilge pump takes care of it.

 

[bds85466]

Re: Small leak in cooling manifold

Yeah apologies for beating this post down before I have the proper info, but I figure if it's a very fine hole (though holes will always get bigger) based solely on the stream of water I saw at dusk the other night. The leak may be taken care of by the bilge, but I'd prefer it not to be blown open at some point and I overheat out on the lake. If it truly is a hole all the way through the manifold, I could probably clean/JB Weld it for the time being as I look for a new manifold. If it's a leaky/rusty frost plug, I may be able to simply clean it up and replace the plug(?).

Again, sorry I can't bring any new info to this post until tomorrow -- sadly I've been running around doing OTHER stuff than boating related activities. The weather here has been super rainy. It's crazy we got like 4-5 in of rain in all of June and July (anyone else think this has been a mild summer?) , and now bang, some places have got over 10 in the last two weeks.

 

[jtybt]

Re: Small leak in cooling manifold

Try some of that silver or brown powder stuff in the little plastic tube. One of the 'stop leak' products.

I had a very small leak at a freeze plug but wasn't worth draining the antifreeze.


...if you are raw water cooled you can still add the stuff but you have to block off hoses to keep water in the block...and, depending on the type of raw water pump, disable or re-route the water hose temporarily.


Oh yeah, you may have to stop the engine and let cool down a couple of times with a blocked off cooling system so it doesn't overheat.

 

[bds85466]

Re: Small leak in cooling manifold

Can I change the thread title? Not sure if it's applicable anymore:redface:

These pictures are terrible, it was pouring rain here yesterday and I didn?t feel the need to bring a digi down to the dock, so those are from my cell phone circa 2003.

Some worse than expected news came after I got the seat out of the way and actually inspected the leak. It appears that there?s more than one leak and quite a bit of rust. As you can see from the pictures, the rust runs in a band vertically and wraps from the side of the manifold down to the bottom. The top leak looks to be shooting straight portside and the bottom one, on the bottom of the manifold is shooting down/port at about a 45 degree angle. From the looks of it, I get the thinking that there was always at one point a crack here going across the whole manifold and finally the previous owner?s weld is giving way. You can actually see the crack continuing up towards the top of the manifold.

At any rate, it looks to me (though I?m not an expert) that this manifold is shot. The only thing worth doing is replacing it right? My thought was in the meantime that I would clean up the rusty crap and JB weld the really rough/hole spots as I await a new manifold.

I?ve never done any sort of engine work like this, so I appreciate any advice. Can anyone verify this info on the OEM manifold?

I/O: 1982 Merc 898

Exhaust Manifold (guess): 77234A2
Sierra replacement: 18-1950-1

It appears that the starboard and port side manifolds are different, but I believe the above number is for the port side if I looked it up correctly. Do these parts usually include the necessary gaskets, mounting screws, plugs, etc?

Thanks any/everyone for their help.

 

[TowRoper]

Re: Small leak in cooling manifold

is this what you need? i dont know merc's very well but i seen this on cregs list
http://portland.craigslist.org/clk/boa/1334864352.html

 

[bds85466]

Re: Small leak in cooling manifold

Thanks for the lead, but no. Mine's a V8 not an inline 6.

 

[TowRoper]

Re: Small leak in cooling manifold

oops :redface:

 

[bds85466]

Re: Small leak in cooling manifold

bump,

anyone?

 

[Bondo]

Re: Small leak in cooling manifold

Ayuh,... Donno,... Is the drain plug missin',..??

 

[bds85466]

Re: Small leak in cooling manifold

I don't think so. I put JB weld over the holes/crack and it supressed the bleeding for now. I'm really looking to replace the manifold, can anyone confirm which I would need?

It's the portside manifold...

I/O: 1982 Merc 898

Exhaust Manifold (guess): 77234

 

[bds85466]

Re: Small leak in exhaust manifold

Re: Small leak in exhaust manifold

well, if anyone was looking for a good deal on manifolds of this type, after shopping around I found an aftermarket site which had very good pricing on both parts and shipping:

http://marineengineparts.com/

Many places have this manifold for $300's, whereas I got mine with shipping for like $250.