Manifold to cat pipe gaskets

[IPAddis]

My exhausts are blowing on both sides from the join between the manifolds and the cat Y-piece (near the lambda sensors). The steel band that holds the pipes together has some slots cut into it and there is noticable soot deposits and tapping noise coming from the area.

I have tried to tighten up the clamp but it has made no difference. Should there be a gasket in between the two sections or do I just need some new clamps? Is it worth blocking the slots with exhaust repair stuff?

Regards,

Ian A.

[IPAddis]

NE1?

[Midnight Blue]

No gasket, just use a little exhaust sealing paste. The ends of the two parts are 'stepped' to lock together better.

Be careful taking it apart, the tubular manifolds get slightly warped with the heat. As they are bolted firmly to each side of the engine there isn't a lot of give in the system, so getting it back together again can be a right s*d.

[Leadfoot]

Those clamps should be tapped with a hammer aound their circumference as you tighten them up. Might be worth backing them right off & trying again?
Don't bother blocking up the slots, the clamp doesn't provide a gas tight seal - the pipe to pipe fit does this.