Coolant where it shouldn't be

[ontherocks83]

I am in the middle of doing a meidum sized "refit / reno" on my new to me boat this winter. During one of my projects after I removed the engine, I then removed the exhaust manifold/coolant manifold reservoir thingy (I'm not quite sure what to call it but it is an exhaust mainfold on the bottom half and a coolant reservoir on the top half, anyways.........

There are only 6 studs that hold it on and when removing one of the studs there was a signifcant amount of coolant that came out one of the stud holes in the manifold (see manifold picture, it was one of the circled holes though I can't remember exactly which one)

Looking at it more today, I realized there is no way that I can see that coolant should ever have made it in to the stud hole. (if you see the picture of the inside of the manifold there is a passage way for each stud that should be sealed off from the coolant.

Normally I am of the mindset that, when in doubt replace it, but......... a new manifold from westerbeke/universal is $1500. Although if need be I will go down this route I am praying there may be another solution as there are a lot of other things on this boat that $1500 will be very useful towards.

Does anyone know if there is a work around for this i.e. since there is not a lot of pressure in the system, can I just seal off each side of the stud holes when installing it and be good or do I just need to bite the bullet and watch my refit budget keep creeping up?

[nhschneider]

On many engines, the threads for manifold studs do penetrate into a coolant jacket. When replacing the stud, I'd recommend that the threads be coated with an appropriate sealant.

Fair winds and calm seas.

[ontherocks83]

Originally Posted by nhschneider

On many engines, the threads for manifold studs do penetrate into a coolant jacket. When replacing the stud, I'd recommend that the threads be coated with an appropriate sealant.

Fair winds and calm seas.

I know on engines like a chevy/Mercruiser 350 that is the case but on this manifold it looks like they were specifically designed to not do that and have their own specific "tunnel" to go through. If I can get away with putting sealant on all the studs and not risk anything i'll be ecstatic but if there is a significant chance of it failing at the worst moment possible then I'd rather replace it.

[Stu Jackson]

There is a detailed discussion about this here:


https://marinehowto.com/


Will take you some quality time to find it.

[ontherocks83]

Originally Posted by Stu Jackson

There is a detailed discussion about this here:


https://marinehowto.com/


Will take you some quality time to find it.

Oh man, I thought I was a renowned scholar when it came to the amount of time I've spent studying his website, but I don't recall an article on this issue. Oh well, back to the University of Maine Sail I go

[seabreez]

Originally Posted by ontherocks83

ld be sealed off from the coolant.

Does anyone know if there is a work around for this i.e. since there is not a lot of pressure in the system, can I just seal off each side of the stud holes when installing it and be good or do I just need to bite the bullet and watch my refit budget keep creeping up?

When I rebuild engines, I always measure the bolts and seal off the top threads where the two surfaces meet. It is good practice and seals the coolant from migrating up the threads and does not jam the bolts in the blocks or heads. Another practice is to pass a thread chaser in every thread bolt in heads, blocks or any other mounting brackets. Then check to see any bolts to make sure there is no stretch in the threads. Peace of mind...