Catalyst legality (in multi-cat sytems)
Discussion
My Google-fu is letting me down here, so any informed opinions welcome. It is a legal question, not a mechanical one, honest!
From what I have been told, my dad's old Mondeo V6 2.5 needs a new downpipe, which the garage is unable to source. For time and foul weather reasons, I haven't yet been able to see precisely which part of the exhaust system is failing. It seems it may be the pipe that connects to the front exhaust manifold, and which contains the primary close-coupled catalyst. The rear bank has a similar one, they then connect to a Y-piece, and the main catalyst.
Ebay is only producing results for one £600 item (I guess it would need both banks really), which isn't going to happen. However, there seem to be several suppliers of stainless steel systems (manifolds, plain downpipes, Y-piece) for under £300. Now, I know legislation regarding cat changes has recently come into effect, and the cat must be present and unmolested for testing. In this instance, the main cat would still be there. I understand that the close-coupled downpipe cats are there only to work during engine warm-up, so there shouldn't be any impact on tested emissions at MoT time.
Does the legislation cover older (1998 in this instance) cars? Presuming emissions are still fine, and the main cat is still present and working. It may well be that in such a tight engine bay, without detailed inspection nobody would notice, but still..
From what I have been told, my dad's old Mondeo V6 2.5 needs a new downpipe, which the garage is unable to source. For time and foul weather reasons, I haven't yet been able to see precisely which part of the exhaust system is failing. It seems it may be the pipe that connects to the front exhaust manifold, and which contains the primary close-coupled catalyst. The rear bank has a similar one, they then connect to a Y-piece, and the main catalyst.
Ebay is only producing results for one £600 item (I guess it would need both banks really), which isn't going to happen. However, there seem to be several suppliers of stainless steel systems (manifolds, plain downpipes, Y-piece) for under £300. Now, I know legislation regarding cat changes has recently come into effect, and the cat must be present and unmolested for testing. In this instance, the main cat would still be there. I understand that the close-coupled downpipe cats are there only to work during engine warm-up, so there shouldn't be any impact on tested emissions at MoT time.
Does the legislation cover older (1998 in this instance) cars? Presuming emissions are still fine, and the main cat is still present and working. It may well be that in such a tight engine bay, without detailed inspection nobody would notice, but still..
Many TVR Griffith and Chimaera owners remove the pre-cats from the exhaust manifolds but leave the main one in place. They are also only there to keep emissions low until the engine is hot. Since you cannot tell by the external appearance, and they pass the emissions test when warm nobody would know apart from a slight change in engine tone to an aficionado.
If the pipe without a pre-cat looks the same, you'd probably be OK. Unless it's obvious that a cat is missing from one bank that is? Would you be able to see from underneath or are there covers underneath the car?
If the pipe without a pre-cat looks the same, you'd probably be OK. Unless it's obvious that a cat is missing from one bank that is? Would you be able to see from underneath or are there covers underneath the car?
2 points...
1) My dad had a 1998 V6 Mondeo when I was young and loved it, I can't remember the last time I saw one now :/ Well done to your dad for keeping one going!
2) Is it so far gone that it can't be repaired? Most garages wouldn't want to as it's a not a pleasant job, but it could possibly be patched up by someone that knows what they're doing....
1) My dad had a 1998 V6 Mondeo when I was young and loved it, I can't remember the last time I saw one now :/ Well done to your dad for keeping one going!
2) Is it so far gone that it can't be repaired? Most garages wouldn't want to as it's a not a pleasant job, but it could possibly be patched up by someone that knows what they're doing....
If it passes the MOT emissions test when up to temperature, knock the guts out of the pre-cats and keep the casing (if it would be obvious if they were missing), fit a straight-through section in the middle (to maintain flow), fit and forget.
Or just swap for a straight-through section if there isn't an obvious gap that the pre-cat casing fills.
Or just swap for a straight-through section if there isn't an obvious gap that the pre-cat casing fills.
Illegal; yes. "Potential penalties are unlimited fines"
https://www.gov.uk/government/publications/modifyi...
And unless you can find a corrupt MOT tester who will take a bribe, it's a major failure of the test.
https://www.motester.co.uk/mot-test-of-exhaust-sys...
https://www.gov.uk/government/publications/modifyi...
And unless you can find a corrupt MOT tester who will take a bribe, it's a major failure of the test.
https://www.motester.co.uk/mot-test-of-exhaust-sys...
NMNeil said:
Illegal; yes. "Potential penalties are unlimited fines"
https://www.gov.uk/government/publications/modifyi...
And unless you can find a corrupt MOT tester who will take a bribe, it's a major failure of the test.
https://www.motester.co.uk/mot-test-of-exhaust-sys...
If the empty casing is there (or is not obvious in its absence) and it still passes the emissions test as prescribed within the MOT procedures, I'm not sure how any individual MOT tester would know anything was 'wrong'.https://www.gov.uk/government/publications/modifyi...
And unless you can find a corrupt MOT tester who will take a bribe, it's a major failure of the test.
https://www.motester.co.uk/mot-test-of-exhaust-sys...
RSTurboPaul said:
NMNeil said:
Illegal; yes. "Potential penalties are unlimited fines"
https://www.gov.uk/government/publications/modifyi...
And unless you can find a corrupt MOT tester who will take a bribe, it's a major failure of the test.
https://www.motester.co.uk/mot-test-of-exhaust-sys...
If the empty casing is there (or is not obvious in its absence) and it still passes the emissions test as prescribed within the MOT procedures, I'm not sure how any individual MOT tester would know anything was 'wrong'.https://www.gov.uk/government/publications/modifyi...
And unless you can find a corrupt MOT tester who will take a bribe, it's a major failure of the test.
https://www.motester.co.uk/mot-test-of-exhaust-sys...
RSTurboPaul said:
If the empty casing is there (or is not obvious in its absence) and it still passes the emissions test as prescribed within the MOT procedures, I'm not sure how any individual MOT tester would know anything was 'wrong'.
True. And there's a whole industry devoted to breaking the law by selling and fitting emissions control tampering and/or removal services, so it is difficult for the MOT tester to tell.Thanks folks.
I thought I should post an update, so you know I'm not ignoring you. Not that there is much to update, as it seems to have been raining constantly since I made the original post, and combined with heavy duty Christmas food/drink imbibing, I probably couldn't actually get under the car right now.
I _think_ that it is one of the primary cats that is blowing. I'm not looking to gut them, just stop them blowing. If new Ford parts were available then they would be in now. Having done a fair bit of looking around the web though, it seems some people call the Y-pipe the downpipe, which (if it is that which is blowing) would make life a whole lot easier. If it is the Y-pipe, then I'm also surprised the garage couldn't just weld on a patch. They are just a local garage, but alas were taken over by Halfords recently. Having said that, the manager is still the same chap, and he has always been open and honest in the past, and has gone the extra mile. e.g. If I can source the part, he will fit it, unlike most places now.
Depending on what I find, Gun Gum + patch may be an option. I hadn't considered that. Obviously, if it is actually on the primary cat then that's unlikely to survive. The noise it makes is more like a rattling/graunching heat shield (I'm assured it isn't) and although it is blowing slightly, being a V6 it is inherently smooth and still quieter than an idling petrol 4-cylinder.
On the subject of replacing the cats, it seems to be the case that you buy a whole stainless steel assembly, from manifolds to Y. The primary cats on their own are probably pretty invisible, especially if the undertray were reinstalled (that disappeared years ago). Not sure how much more noise a through-pipe on the primaries would make, dad had a slightly louder back box put on a few years ago, but unless you go beyond 3500rpm they are pretty quiet. V6 Mondeos are rare enough that an average MOT mechanic in a workshop with diesels around wouldn't notice if they were a bit louder.
The main reason we still have the car is - what on earth do you replace it with? It only does 2-3000 miles a year so economy isn't critical, but anything much newer with a similar sized engine and you are into £500+ tax, and anything over 10 years old is still going to be into repair bills, so better to keep this and repair it if possible. We tested a couple of Mk4 Mondeo 2.2 titanium X diesels a few years ago and they didn't work for either of us, and were a bit too big for either our needs. Nice torque, but ClatterClatterClatter and more than a whiff of taxi. I pointed out some BMW 325/330/335s but the response wasn't enthusiastic. When someone asked if he might like a nice Yaris instead, they received a withering Paddington-like stare.
Fingers crossed the rain stops and I can get a look at the offending article!
Thanks again, and merry day-after-boxing-day-mas!
I thought I should post an update, so you know I'm not ignoring you. Not that there is much to update, as it seems to have been raining constantly since I made the original post, and combined with heavy duty Christmas food/drink imbibing, I probably couldn't actually get under the car right now.
I _think_ that it is one of the primary cats that is blowing. I'm not looking to gut them, just stop them blowing. If new Ford parts were available then they would be in now. Having done a fair bit of looking around the web though, it seems some people call the Y-pipe the downpipe, which (if it is that which is blowing) would make life a whole lot easier. If it is the Y-pipe, then I'm also surprised the garage couldn't just weld on a patch. They are just a local garage, but alas were taken over by Halfords recently. Having said that, the manager is still the same chap, and he has always been open and honest in the past, and has gone the extra mile. e.g. If I can source the part, he will fit it, unlike most places now.
Depending on what I find, Gun Gum + patch may be an option. I hadn't considered that. Obviously, if it is actually on the primary cat then that's unlikely to survive. The noise it makes is more like a rattling/graunching heat shield (I'm assured it isn't) and although it is blowing slightly, being a V6 it is inherently smooth and still quieter than an idling petrol 4-cylinder.
On the subject of replacing the cats, it seems to be the case that you buy a whole stainless steel assembly, from manifolds to Y. The primary cats on their own are probably pretty invisible, especially if the undertray were reinstalled (that disappeared years ago). Not sure how much more noise a through-pipe on the primaries would make, dad had a slightly louder back box put on a few years ago, but unless you go beyond 3500rpm they are pretty quiet. V6 Mondeos are rare enough that an average MOT mechanic in a workshop with diesels around wouldn't notice if they were a bit louder.
The main reason we still have the car is - what on earth do you replace it with? It only does 2-3000 miles a year so economy isn't critical, but anything much newer with a similar sized engine and you are into £500+ tax, and anything over 10 years old is still going to be into repair bills, so better to keep this and repair it if possible. We tested a couple of Mk4 Mondeo 2.2 titanium X diesels a few years ago and they didn't work for either of us, and were a bit too big for either our needs. Nice torque, but ClatterClatterClatter and more than a whiff of taxi. I pointed out some BMW 325/330/335s but the response wasn't enthusiastic. When someone asked if he might like a nice Yaris instead, they received a withering Paddington-like stare.
Fingers crossed the rain stops and I can get a look at the offending article!
Thanks again, and merry day-after-boxing-day-mas!
MOT tester told me one part of the test involves sticking the probe up the exhaust & leaving it there for approx 20 mins whilst the system is connected to the governments online system which measure emissions....... (this is why they can now only do in working hours for the system being online servers wise at the governments end as it shuts for maintenance).
Any exhaust emissions control equipment that is missing, obviously modified or obviously defective is a major, but a typical MOT tester isn't going to know the specifics of every car, if its got a big cat where they expect there to be a cat, its going to pass, unless you take it to a specialist who knows the model well, but they'll probably be fairly sympathetic and ignore it.
IME an MOT tester will look only at the emissions test results.
If it passes, it passes. If it fails, it fails, and they won’t be interested in working out why it has failed unless it is glaringly obvious.
A car with primary and secondary cats will generally be easier to get through an MOT if the secondaries have been removed, because the primaries are larger and closer to the heat of the engine. Remove the primaries and maybe (depending on the car I guess) you might need to get the secondaries up to temperature to pass, and a bog standard disinterested MOT tester may be disinclined to piss around doing what’s needed to do that.
If it passes, it passes. If it fails, it fails, and they won’t be interested in working out why it has failed unless it is glaringly obvious.
A car with primary and secondary cats will generally be easier to get through an MOT if the secondaries have been removed, because the primaries are larger and closer to the heat of the engine. Remove the primaries and maybe (depending on the car I guess) you might need to get the secondaries up to temperature to pass, and a bog standard disinterested MOT tester may be disinclined to piss around doing what’s needed to do that.
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