Catalitic Converter

[Northumbrian]

Does a cat converter which is probably past its prime give any warnings before a complete failure and loss of power? I have a buzzing noise which I thought might indicate early blowing of the exhaust but there is no problem with the main body of the system. The noise is up front near the manifold.

[david1702198]

maybe a heatshield starting to come unsecure??common problem on most cars

[spaced]

get it checked out, as a cat converter is might costly

[Toureman]

If it fails it does not lose power.

You can get a rattle noise inside it if it starts to break down.

Where is the cat in your exhaust system?

[aeinstein]

agree that it sounds like a heatshield. it is possible that the insides of the cat is coming loose. best thing to do is trace exactly where the noise is coming from.

btw, toureman, if a cat collapses inside, it causes the car to feel like its 'strangled' and will get worse the further you drive, ie as it gets hotter.

[Northumbrian]

Thanks to you all. The vehicle is a 99 Mitsubishi Carisma 1900 DOHC and the converter appears to be situated just for ward of the front seat well. There is a short front pipe between the manifold and the converter and, I think, a heat shield under the well.