New Upper Exhaust Tube Gasket Leaking

[whitefish1]

When I replaced the exhaust shutter on my '93 Mercruiser 3.0, I removed the upper exhaust tube. I cleaned up the surfaces on the manifold and the tube down to metal (mostly) and put on a new Merc gasket. I reinstalled the upper exhaust tube and torqued to 25 ft/lbs. I started the engine up and I got a small leak at this gasket (more of a weep than an actual leak). I would say its about a teaspoon every couple of minutes at idle. Should I pull and add a small amount of gasket sealer, or will this seal over time?

As an aside, the other thing I noticed is that the new (and old) gasket partially covered the water jacket galleries on both sides of the manifold/upper exhaust tube union. Is this right? Seems weird to me.

 

[Don S]

Re: New Upper Exhaust Tube Gasket Leaking

What was the condition of the gasket surfaces of the manifold and exhaust elbow (Not tube)? You shouldn't have any leaks at all.

 

[whitefish1]

Re: New Upper Exhaust Tube Gasket Leaking

Hi Don - sorry when I said "tube" I meant the upper exhaust elbow.

I cleaned off the old gasket material from both mating surfaces - I used a razor blade being careful not to gaul the metal. The mating surfaces looked fine - nothing warped or rusted.

The only thing I can think of is a piece of foreign material got in between when I put the gasket on.

 

[whitefish1]

Re: New Upper Exhaust Tube Gasket Leaking

I torqued down the exhaust elbow bolts a wee bit more - problem solved.