Catalytic converter failure query?

[mickl]

no, it's not happened on mine...touch wood!

just wondering if there are any outward signs that a cat converter is about to die without strapping it to an emissions tester?

new MOT due soon and these sorts of questions play on your mind

 

[Stratman]

There are two types of 'death' for a cat. It can expire mechanically, where the platinum coated honeycomb breaks up and comes away from its support. This can be caused by heat shock, such as driving through a deep puddle. This causes the various parts to rapidly contract, unfortunately at different rates. There is only one outcome
The "Death Rattle" from underneath the car can indicate this.

Bouncing it off speed humps is another popular way of wrecking it.

It can also expire chemically. The platinum catalyst becomes 'poisoned' with impurities over time, especially before it reaches its operating temperature. This is why cat-equipped cars go to great lengths to ensure a quick warm-up. Unfortunately the only way to spot this is by putting on an emissions tester.

 

[mickl]

There are two types of 'death' for a cat. It can expire mechanically, where the platinum coated honeycomb breaks up and comes away from its support. This can be caused by heat shock, such as driving through a deep puddle. This causes the various parts to rapidly contract, unfortunately at different rates. There is only one outcome
The "Death Rattle" from underneath the car can indicate this.

Bouncing it off speed humps is another popular way of wrecking it.

eek!! have scraped the bottom of the car a couple of times due to the slope of the driveway and neighbours parking not giving me enough room to reverse in at the correct angle

 

[Alps]

mines so low, the CATS always getting a battering! although its more of a scrap than a bang on the cat, and i do drive Veeeery slowly over speed humps!

 

[mickl]

yeah, its more a scrape, never banged it (I don't think!) and thats at crawling speeds. Never scraped it on speed humps, always take them very slowly, just some rubbing from the tyres on the inner arch liners due to the 18" rims

 

[Satch]

There is a process that involves washing Cats. for diesels out with a dilute Citric Acid solution at 85C for 6 hours. That strips a lot of the nasty stuff out including Sulphur and Phosphorus contamination. Providing the matrix and Platinum coating is not damaged renders them nearly as good as new.

Not heard of anything similar for petrol engine cats though.