I’ve been doing an oil change on my 2009 NC Auto today and while I was underneath I noticed the catalytic converter casing had rusted through. As you can see from the picture it’s a fairly big hole. There’s no leakage of exhaust gases and as the car passed the emission test at MOT earlier this year I assume the cat is doing its job. It wasn’t even mentioned as an advisory on the MOT.
I confess that Catalytic Converters aren’t usually a on my radar when maintaining my cars but seeing this hole made me stop and think. If it was part of the exhaust I’d probably be repairing the hole but I’m not sure whether I should do anything in this case? It seems rusted cat casings are quite common. Any thoughts?
I’ve no idea how the MoT tester didn’t see that hole. It’s not exactly difficult to spot it and it would be a definite MoT fail. It’d difficult to understand how it’s not leaking exhaust gas. I’d have expected it to be an audible leak. I think it needs repair or replacement.
JS
It’s only the heat shield and nothing to do with the MOT so don’t worry about it.
If and when it gets to the point where it’s getting ready to fall off and you still want it on then you can link some very large jubilee clips together and strap it on.
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Well it is just the outer protective casing that’s rotted through. If you look at the photo there are two other visible holes in the casing already, by design, one round and one rectangular right next to it, presumably they’re for drainage. So that’s why it’s still gas tight. Perhaps that’s why the tester passed it?
Having said this, my reaction initially was much the same as yours!
Brilliant thank you, that sounds logical. I’ll do as you suggest and forget about it. 
