Beetle catalytic converter

[Gruff Eddie]

Hi there

My wifes lovely Beetle has just failed it's MOT on emmissions, and I've been told that the catalytic converter needs replacing. The price quoted is astronomical for a VAG part, and an after market variant seems much cheaper.

My mechanic has advised against after market parts on the car, but thought it would be worth an ask to see if anyone had any experience of them?

Many thanks in advance

Gruff Eddie :)

[Crasher]

The genuine units are much stronger, pattern cats can be extremely fragile and personally I would rather have a used original than a pattern new one. The problem is that this does not address why the cat has failed, very rarely do they fail for no reason. Fit a delicate pattern cat to a car with a running problem and you will soon have another faulty cat and it will not be covered under the manufactures warranty.

[Gruff Eddie]

Hi Crasher

Thanks for the speedy reply. There are no other problems with the car. It runs well, and there are no engine management lights on the car.

It does low mileage though - less than 5,000 in the last year, and most of these are silly little journeys, so the car doesn't get up to temperature very often. My mechanic reckons this is the problem - petrol gets left in the cat and it get burned off and burns out?

Does this sound likely?

Point noted about the after market parts - I thought this was probably the case, but was tempted when some of them offer a 2 year warranty.

Thanks again,

Gareth

[Crasher]

In that case it does not explain why the cat has failed, they are extremely robust and I hardly ever replace one even after they have been through hell with all sorts of running problems. What year and engine code is the car? Two year warranty or not (which is what the genuine units has but it also includes labour), no warranty will cover the cat if it fails due to external influences.

[Gruff Eddie]

The car is a 2l petrol, and it's a 2000 on a W plate. It's just ticked over the 70,000 miles marker.

Are there any other reasons that the emissions might be so high?

[Crasher]

Do you have the engine three letter code? Such as AZD or similar.

[Gruff Eddie]

Sorry for being such a novice. Where would I find such a thing?

Here's the emission read out - not sure if it's any use to you or not?

The registration on the read out is actually a digit wrong. Am I being done?

[Crasher]

It is in the service book. I can't read that emissions printout.

[Gruff Eddie]

It looks like the forum has resized it for some reason. Here's the original scan
http://www.familysharp.plus.com/gareth/picx/scan0001.jpg
(http://www.familysharp.plus.com/gareth/picx/scan0001.jpg)
The engine number is AQY EPB

Thanks again for your help, and for your patience!

[Crasher]

The fast idle and natural idle readings are indeed a failure but the clue here is the natural idle Co reading, this is far too high for the car even if the catalyst was missing as I would expect an uncatalysed Co of around 1% at lambda 1 which the engine is hovering around so OK there. The AQY is full OBDII with an after cat lambda sensor which should pick up any emissions issue so that concerns me as well. Something does not add up, I am quite sure that the problem is not the cat itself due to the 2.26% idle Co and would start my diagnosis with a fault code read. I think that with the engine problem I think it has cured, the cat will recover. It could just be something as simple as a failed coolant temperature sender or an inlet boot air leak.

[Gruff Eddie]

Hi Crasher

Many thanks for your wise words. I think I'm going to get it booked in to have the codes read - sounds like the best way forward.

Fingers crossed whatever is wrong with it comes in less than the cat!

Thanks again,

Gareth

[Gruff Eddie]

Hi there

Just a quick update for you, I took the car to an alternative garage, they replaced one of the lambda sensors, and job's a good 'un :D

Significantly cheaper than getting the cat replaced!

[Crasher]

As I said, if the cat had been replaced, it would have failed again and who would have picked up the tab?...Feed a cat crap and it will work like crap.

[Gruff Eddie]

It would have cost me a cat, and would have cost me a whole lot more I reckon!

I'm really glad I got some advice here and got a second opinion from a different garage - save me at least £750!.