www.iFourWinns.com

I am getting ready to replace the exhaust manifolds and risers in my 1996 Horizon 190 with a Volvo Penta (OMC) 4.3 engine. I have conflicting information on the use of sealant in the manifold to head and riser to manifold connections. I intend on using a thin coat of high temp rtv on both sides of the exhaust manifold gasket and permatex 2 (non hardening sealer) on the riser joint. Any guidance you can provide is greatly appreciated.

There's a Volvo penta Service bulletin out there about this; 25-1 16 01; they changed their minds in April 2010 and recommended the use of certain sealants from then on for the riser to manifold joint , whereas before there were none used. If you can't find the Service Bulletin, the products recommended are:

Permatex Copper Spray-a-Gasket (80697)

K&W Copper Coat (401612)

They state this applies to all gas engines with cast iron manifolds and risers from 1993 and does not apply to catalyst gas engines or pre JV gas engines

Do not use RTV, Copper gasket spray is what you should use on them.

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Brian Borchik
The Winds of Cold Springs Harbor Marina
Baldwinsville, NY

I would not use anything on the Manifold Gasket (Manifold to Engine). There is no water passing through that gasket, only exhaust, so there is no worry about water getting in your engine because of that gasket having a trace of a leak.

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"Knot Easy" 2000 Horizon 240 Volvo 5.7GS /SX
tow: 2017 Honda PILOT EXL-AWD
prev. boats:
'87 Chaparral 198CXL 4.3 OMC Cobra
'69 Jetstar 16ft Ski Boat, 115hp Yamaha
'68 Aluminum Jon Boat, 3hp Sears
'64 Water Wings

The manifold to head gaskets rarely fail, its the manifold to riser gaskets that can fail and let water leak in a cylinder. Apparently these were a problem on certain year Volvos and the gaskets were changed and the recommendation for the spray sealer was made. I think Volvo issued a TSB on this but it was a number of years back.

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

Brian, no disrespect intended here as I read all of your posts and learn a lot from you. Permatex does make a copper based RTV for exhaust applications. One of my clients with twin supercharged 502 MPI Mercs kept blowing the header to riser flange gasket. This stuff did the trick. Just in case you didn't hear about it

John

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07 Azure AZ200,
Previous boat,
95 278 Vista,
And a lot of others.

Ontario, Canada

Yep - +1 to Brians comment. Definitely Permatex Copper Spray is what VP recommend on the latest TSB - just done mine in July.

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Alec

2006 Horizon 190
VP 4.3GL/SX, Sunsport

Not to be negative, but this is one part of a boat engine that is just like an auto engine. True, there is no water there, but cast iron against metal (or aluminum) is not the best of mating surfaces, especially with heat making it expand and contract constantly. An exhaust gasket will fill that "gap", and stop compression loss, not to mention the annoying PSSST PSSST PSSST a exhaust leak makes.

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1996 205 Sundowner DLX
5.0FL Volvo SX Cobra
Tow Veh: 2012 Nissan Frontier Pro-4X

I never take anything personally, even when people disagree. If you are talking about the red copper RTV, I know an engine builder that likes that stuff and swears by it. I personally have never used it. I have had many experiences where RTV blows out or leaks over time, but since I started using the copper gasket spray on everything I have never had issues.

_________________
Brian Borchik
The Winds of Cold Springs Harbor Marina
Baldwinsville, NY

I was not suggesting to omit the gasket... I was simply stating that RTV would not be a necessary addition to the gasket.

_________________

"Knot Easy" 2000 Horizon 240 Volvo 5.7GS /SX
tow: 2017 Honda PILOT EXL-AWD
prev. boats:
'87 Chaparral 198CXL 4.3 OMC Cobra
'69 Jetstar 16ft Ski Boat, 115hp Yamaha
'68 Aluminum Jon Boat, 3hp Sears
'64 Water Wings

Ooops, yeah just re-read that....I guess that word GASKET in your post should have given me my first clue.

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1996 205 Sundowner DLX
5.0FL Volvo SX Cobra
Tow Veh: 2012 Nissan Frontier Pro-4X

I found information on how the exhaust manifold connects to ????? I completely understand how to connect my manifold to my risers but what do I need to know about connecting the manifold to the (block? engine?) I'm not even sure what it connects to or if I need to apply any sealant to the connection. I would like to replace them this weekend but need to make sure I have what I need and know exactly what to do.

On the small block V8 the manifolds are attached to the heads with 6 bolts. You'll have to clean both the manifold and head surfaces to remove all traces of the old gasket; which may not be as easy as it sounds ! Make sure you block off the exhaust ports on the head, to stop anything falling in as you are cleaning the old gasket off.

The gasket does not need the same adhesive as is recommended for the riser gasket; there is no water passing through from the head to the manifold. You'll find it easier to keep the new gasket in the right place if you make up 2 studs to "hang" it from ; those studs will also allow the (heavy) manifold to be slid into place.

SPAM!

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"Knot Easy" 2000 Horizon 240 Volvo 5.7GS /SX
tow: 2017 Honda PILOT EXL-AWD
prev. boats:
'87 Chaparral 198CXL 4.3 OMC Cobra
'69 Jetstar 16ft Ski Boat, 115hp Yamaha
'68 Aluminum Jon Boat, 3hp Sears
'64 Water Wings

Really? I didn't regognise it as such. Never mind.