exhaust manifold to elbow gasket & sealant

[willxfs]

Here's an easy one. I'm changing out the exhaust manifold/elbow and risers on a 1998 mercruiser 4.3L v6. I have a closed cooling system. On the square gasket in between the manifold and elbow do you need sealant. The merc manual says to use mercury loctite 510 sealant. I'm not sure about using the sealant on the stainless steel gasket. Also what other brand of sealant is suitable. Thanks.

 

[Don S]

Re: exhaust manifold to elbow gasket & sealant

DRY, use OEM gaskets only. The manual is outdated. I will post the bulletin that gives the proper gaskets shortly.

 

[Don S]

Re: exhaust manifold to elbow gasket & sealant

Here is that service bulletin.

http://www.boatfix.com/merc/Bullet/99/99_10.pdf

 

[willxfs]

Re: exhaust manifold to elbow gasket & sealant

Thanks Don. That's what I was looking for. One more quick question. I bought some GLM manifolds, elbows and risers that came with GLM gaskets. Should I ditch these and get the mercruisers. Also I'm confused on what style gasket I need. The GLM's are the restrictor but with only one small hole in the middle of the fore and aft side. They have slots on the port and starboard side. I have a closed cooling system with raw water cooled manifolds/elbow's. The updated service bulletin says I need the 4-slot gasket. Thanks.

 

[Don S]

Re: exhaust manifold to elbow gasket & sealant

Have never used GLM manfolds and risers, I don't even know if the OEM gaskets will fit or not.
If the GLM's are copies of the OEM manifolds, I would use the gasket setup Merc suggests.

 

[Bondo]

Re: exhaust manifold to elbow gasket & sealant

I bought some GLM manifolds, elbows and risers that came with GLM gaskets. Should I ditch these and get the mercruisers.

Ayuh,.. They're patterned after the Merc.s,+ you definitely want to use the Merc gaskets...
Also,...
Before you mount 'em,...
Closely inspect the gasket faces with a straight edge...
The 1s I have, I had to remachine them to Flatten the surface,...
The outside edges were High, or the inner surfaces were Low,...
I was getting hydro-lock with 'em Brand New...

Since I flattened 'em,.. So far, so Good...

 

[colinpegrum]

Thank you for Posting the service bulletin Don S. Interesting how Mercruiser changed entirely to full flow in example 4a (which I happen to have on my boat). Is this still a current bulletin? My manifolds were install 2 years ago by Mercruiser agent and I just removed due to a nagging elevated core temperature issue. Anyway, nothing wrong with the manifolds, risers or elbows so reinstalling and want to use the correct gaskets of course!