volvo 305 exhaust riser gasket

[pine island fred]

So to repair my friends steam engine he ordered a new exhaust manifold and riser assy. He opens up the box for the riser and finds two gaskets. One gasket looks normal for the riser to manifold , then there is another gasket that is the same but does not have holes for the water passage between the manifold and riser, just the exhaust. Not that we plan to use it but does anyone know what it would be for? thanks fred

 

[jastacey]

Re: volvo 305 exhaust riser gasket

That gasket is for a closed cooling system,I believe

 

[rodbolt]

Re: volvo 305 exhaust riser gasket

some early volvo and aftermarket closed cooling systems used antifreeze in the manifolds as well as the block and just raw water through the risers. that is call a full closed cooling, a half system only cools the block and head assy with antifreeze and runs raw water through the manifold and risers.<br /> I dont think volvo offers a full system anymore, have not seen one in years from volvo.<br /> on a merc its common.

 

[pine island fred]

Re: volvo 305 exhaust riser gasket

Thanks for the info. Was simple if I had thought about it. Never saw a closed cooling system but I avoid getting involved with i/os. Sure seems it would be well worth the extra cost if running in salt water. regards fred