a. I could hear a noise coming from the side of the car.
b. There was a bit of a 'burble' on the overrun.
c. The car was not happy when running in 1st gear after being left for an hour or so. I suspected that was down to the lamda sensor not reading correctly and that would be explained by a leak just in front of it.
d. The car had been marginal on the emissions test, again pointing to the lamda sensor not getting the right readings.
Once I removed the heat shield it was confirmed as there was a distinct sooty deposit on the bodywork.
The lamda sensor is just behind the leak.
So I removed the clamps and the outer tube and it was apparent that there was no corrosion, it was simply that the sealant used by the previous owner had all disappeared and it was simply leaking through the joint.
I decided to repair it using a mix of new ideas and the 'old-school' approach. It meant it is rather 'over-engineered' but that is no bad thing.
So first a liberal dose of Gun Gum (that is what we used to use and is still the best around), followed by a thin aluminimum foil protector.
Followed by an exhaust bandage that solidifies with the heat of the exhaust.
And finally a clamped cover to protect and support the whole thing using an empty Heinz Baked Beans tin (honest!). That is what we used to use 40 years ago and it is still perfectly good.
Result: A quieter exhaust and engine running smoother. Hopefully it will have improved the emissions, I will find out at the next MOT.