MOT and "catalytic converter" on diesels

[defever]

Hello forum users,

I'm noticing that the metal webbing on the flex segment of my downpipe (I still have the original from factory with the "catalyst") is on its way (not on advisory, but I can see it going) and I think I need to replace it before it starts leaking.

So it got me thinking, knowing that genuine replacement part will be £££, can I replace it with cheaper downpipe without the cat... legally.

VOSA MOT Inspection Manual (Jan 2012: MOT inspection manual for class 3, 4, 5 and 7 vehicles - Publications - GOV.UK) does not say anything about catalytic converter on diesel engines for class 4 vehicles. It's not part of diesel engine emission test on section 7.1 (exhaust system for both spark and compression ignition) or 7.3 (exhaust emission for compression ignition).

That's nothing new from what everyone already knows. Diesels don't need cat test. Simple...

HOWEVER! MOT Special Notice Update on Jan 2014 (MOT special notice 01-14 - Publications - GOV.UK) mentions this:

Item 1: Presence of Catalysts and Particulate Filters on Diesel Powered Vehicles (relevant to AEs & NTs Classes 4, 5, 7)
On 16 February 2014 Section 7.1 of the inspection manual will be amended to include a check for the presence of catalysts and particulate filters on diesel powered vehicles. Any vehicle where a catalytic converter or particulate filter is missing where one was fitted as standard will fail the test.

That's quite clear isn't it. If your car, regardless of age, was fitted with a "catalytic converter" or PDF at factory, you MUST have one fitted at the inspection. My AFN have a "catalyst" on downpipe so I will need to have the "catalyst".


I wanted to share this to fellow B5 1.9TDi owners who may be misinformed on the subject. This is what I found and how I understood it. I'm sure there are fellow forum users here with their own garages and MOT test centres who can correct me if my interpretation is incorrect!

[zollaf]

thats if the tester knows yours had a catalysing filter from factory, when they were not fitted as standard. this is meant more for post 2008 cars with a dpf. your filter was not needed to pass any emissions test at time of manufacture and your car, like my 80 was never type approved as that didn't happen until 2001.

[defever]

I was waiting for you to jump in on this Zollaf, good morning!

You are right and that's what I had in mind too. Unless a tester is nerdy enough to know which model/spec or every car had a cat/DPF from factory, this is pretty difficult for a tester to follow, especially for older cars like ours. Or maybe they a tester can check for this on the new MOT system?

I can also think of few other ways to get around it.

But, VOSA clearly written it that it will fail if a cat or DPF is missing on a car which had it fitted at factory. So if a tester does the MOT correctly, then it's a fail if a cat or DPF is not fitted.

Whether this is implemented or enforced correctly is another matter, isn't it.

Thanks Zollaf!

[Gazwould]

I understood this as VOSA have the information to whether it had a cat.

Sure it's just a visual and can be overcome with an ebay ETS dummy cat etc .

[Eshrules]

Do VOSA still conduct random roadside testing? I wonder how you'd fair with one of these imitation devices with one of those.

[defever]

Gazwould,

Is ETS cat any good quality?

I can see that aftermarket replacement cats can be bought from £60 - £80 on eBay and those are the only ones I can source as replacement.
They all look very similar stainless steel ones so I'm sure a single company is selling those with several different "eBay seller" names.
ECP seem to have non-type approved cat at the price of £44, but it doesn't look like it'll last even a year.

I thought of just having the flex joint replaced by a local exhaust garage but I'm guessing this will cost more than £80 doesn't it.