Exaust fumes getting into car

[Xantidote]

The "brillo" seal is at the back of the engine, fitted at the joint where the exhaust manifold connects into the exhaust pipe. As well as providing a gas tight joint, I think it gives a little flexibility, as the engine moves around a bit. Probably easiest to see by grovelling underneath car, with it supported on axle stands. Can't remember now, but it may be one of those jobs where you do a bit from underneath, and a bit from up top.