LIST OF ACTIONS REGARDING E51/E52 CATALYTIC CONVERTER ISSUES

[RuskinStreet]

There is ceramic in cylinders of every petrol engine - Ceramic insulates the centre spark plug electrode from the outer electrode. But not to worry about ceramics on spark plugs because they hardly ever break up or fail despite being inside the combustion chamber... Spark plug ceramics don't tend to fail unless the engine has been detonating or running too lean a mixture. Lean mixture can increase detonation and increases the potential for oxidation (because if we burn something with a lean mixture there is oxygen left over from the burn, where-as if we burn something with correct or rich mixture there is no oxygen left over after the burn).

We know that the ceramic matrix in Elgrand cats can and does break up.. but it isn't so much the 'heat of the burn' or 'heat of exhaust gas leaving the engine' that causes the cat matrix to break up. Spark plug ceramics look in better condition having run on some fuels that we expect to burn a bit hotter than they do running on other fuels that we expect to run a bit cooler.

There can definitely be a correlation between cat heat and cat failures. If we buy a new Elgrand cat and never fit it to a vehicle, never heat it up, it could sit on a shelf for hundreds of years and the ceramics inside wouldn't break up. If we found the remains of a catalytic converter in an Egyptian pyramid it's likely all the metal would have rusted away but the remaining ceramics would be in perfect condition.

The temperature of a cat isn't only effected by the temperature of the exhaust gas feeding it. Also the more of that gas (like when the engine is burning more fuel) the hotter it will get. And even more so, the more chemical reactions it has to do during cleaning up emissions the hotter it will get. If cats didn't produce heat themselves the hottest they could get would be to equal the temp of exhaust gas but cats get much hotter than heat of exhaust gas. If heat of exhaust gas were extremely hot but there wasn't much of it the cat might not get as hot as it would with a bit cooler exhaust gas but a lot more of it - I can hold my hand a distance over a small flame on a gas cooker but if I increase the size of the flame I would have to move my hand higher over the flame to not burn my hand, yet the small flame and the big flame are at the same temperature. If I ran the cooker on acetylene and oxygen instead of on natural gas and air I could expect to have to lift my hand further because the smaller acetylene flame could have overall more heat than the bigger natural gas flame. If instead of my hand I fitted a catalytic convertor over the cooker, the cat would also see the same incoming heat as my hand but the cat could get hotter than my hand because besides the heat coming from the cooker flame it would make it's own heat doing chemical reactions. When I ran the cooker on natural gas the hottest flame was a nice blue flame, if the cooker were a bit dodgy and gave a yellow flame it would be cooler. I could have my hand lower over a yellow flame than a blue flame but it isn't the same for a cat... A cat might get hotter over the yellow flame, because with the yellow flame it would make more heat inside the cat.

Nissan did a 'fuelling recall' which was supposed to address the cat problem. Looking at difference in readings from Elgrands that haven't had the recall compared to those that have had the recall the recall changed a few things but only slightly. Without the recall Elgrands continue to inject around 0.5ms of petrol on over-run and run a richer mixture than most engines on full load. After the recall Elgrands inject no fuel during over-run and fuelling enrichment at full engine load is leaned off a little (though is still rich). All cars go rich at full engine load so there's nothing unusual about going rich, or even a bit richer than we might expect. And in practice the fuelling recall seems to have done little to help the cat problem - I wouldn't expect it to either. To me the problem does seem to be a design issue on Elgrands.. design of the front cats, the position of them, and of course the 4 cat setup.

But what you really don't want if you have front cats still in place on Elgrands is overly rich mixture at high engine loads...
High engine loads means lots of exhaust gas flowing (bigger flame on the cooker, though this doesn't tell us the temperature of that flame).
Lean mixture means hotter exhaust gas, though that doesn't tell us the 'size of the flame' or the temperature that the cat will reach because with lean mixture the cat won't make as much heat inside itself, maybe not even with 'bigger flame'.
Rich mixture means cooler exhaust gas, though that doesn't tell us temperature that the cat will reach because again we don't know size of the flame, and with rich mixture the cat will do lots of exothermic chemical reactions which will vastly increase the temperature of the cat, exothermic chemical reactions can see the cat get hotter than it would with a lean mixture even though the temperature it was 'fed' at was cooler with the rich mixture than with the lean mixture.
The base temperature of exhaust gas doesn't directly correlate to the temperature that the cat will reach inside, that can depend more on the reactions the cat does or doesn't have to do inside (mixture, and type of fuel) and size of the flame (how much exhaust gas is flowing).
The worst situation is very rich overall at high engine loads (dirty emissions and 'big flame' so lots of dirty emissions to clean up) but with some cylinders running extremely rich mixture and some cylinders running a bit lean mixture, because then there's both way too much fuel plus oxygen feeding the cat and this will increase the temp inside the cat even more than a very rich mixture.

Wouldn't expect to find ceramic cats in a pyramid because they didn't have cats lol, but we do find Egyptian ceramics. Wouldn't expect to find metal matrix cats because they didn't have cats, and if they did they'd probably all have oxidated away by now ;-)

Jeez @Lpgc you lost me at the end of the first sentence lol...
To sum up - Elgrand cats are shite, made even worse by having two pair in series/parallel. Matters made worse by the average age of our cars and the life expectancy of said cats.
Best solutions..
1. Don't buy an Elgrand
2. If you are stupid enough to buy one then get get some bloke called Simon from Yorkshire to convert you to LPG and rip all four cats out ASAP

Btw @Lpgc the Egyptians did have cats, little furry ones that they worshipped

 

[thebluemax]

So I was just checking out a couple of E51's at a car yard today and had them both idling for about an hour. One was a 2005 and the other a 2007 build. I did a lot of tail pipe snorting. Weird I know. Seemed to take a very long time for the rich mixture smell to abate somewhat. I plugged in the chassis numbers into http://www.Nissan.co.jp/RECALL/search.html and got implemented results on brake rotor and fuel gauge recalls but no mention of overfueling recall. Any ideas why?

just put my chassis number into www.Nissan.co.jp/RECALL/search.html and it came up with 3 lines of results...but I can't read them or understand the results.....any ideas please

 

[JohnK]

just put my chassis number into www.Nissan.co.jp/RECALL/search.html and it came up with 3 lines of results...but I can't read them or understand the results.....any ideas please

Depending on which browser you use you should have an option to translate. May need to click on the three dots in top right corner.
There has been a suggestion that once vehicle is exported all recalls are shown as completed. You can instead email postoffice@Nissan.co.jp with the vin and they will confirm. Usually reply within a day or two.

 

[Unfo]

Jeez @Lpgc you lost me at the end of the first sentence lol...
To sum up - Elgrand cats are shite, made even worse by having two pair in series/parallel. Matters made worse by the average age of our cars and the life expectancy of said cats.
Best solutions..
1. Don't buy an Elgrand
2. If you are stupid enough to buy one then get get some bloke called Simon from Yorkshire to convert you to LPG and rip all four cats out ASAP

Btw @Lpgc the Egyptians did have cats, little furry ones that they worshipped

Lpgc is definitely one of the big brains 'round these parts.

 

[Gwilo365]

Are those prices roughly correct? I've had it in my head it would be around £1500 or so for front decored given what's involved not £400. Maybe those are northern prices. If that's really the case I can stop stressing lol. Years away from a purchase but like to research.

Those prices appear about right.
A manifold back stainless exhaust with a couple of sports cats works be in the region of 1500-1700, from hearing about what Powerflow have charged others.
£400 is what Tojomotors charges for front cat decoring.
@Kenzie (Mary Poppins) has found somewhere not far from him that can do it, but I don't believe we have any reports yet about the quality of the work - while I don't want to suggest some places could be taking chances, there's one report from @Ja2432 of front cat decoring that has gone quite badly. Only one, but the costs of failure mean i get a little wary..

I'd like to get my fronts decored, but the amount of downtime and location mean I will be praying my fronts hold out or harmlessly blow out the back till I can afford a new exhaust system instead.

 

[P4ddy]

1, Don''t buy an Elgrand.

That's the big one for me, but factor in a front decat and lpg conversion instead and enjoy that awesome van. Is it a van?

Me thinking that £1500 price was because of everyone saying really expensive, but £400? expensive? Then choosing a
£100 rear gamble instead after paying £7k+ for a really nice Elgrand. That's like opting to put part worn remoulds on your car I stead of new Bridgestone s all round. When I get one I will be shitting myself driving with just a rear cat decore.

 

[Gwilo365]

1, Don''t buy an Elgrand.

That's the big one for me, but factor in a front decat and lpg conversion instead and enjoy that awesome van. Is it a van?

Me thinking that £1500 price was because of everyone saying really expensive, but £400? expensive? Then choosing a
£100 rear gamble instead after paying £7k+ for a really nice Elgrand. That's like opting to put part worn remoulds on your car I stead of new Bridgestone s all round. When I get one I will be shitting myself driving with just a rear cat decore.

A lot of dealers, the majority, have up to this point decored rears only. As a buyer, it was 'the done thing'.
Decoring fronts instead might start becoming more widespread, as I note vineplace are offering that now.
Obviously, if you've had rears done prior to purchase, as many here have, the breakdown of the fronts and blocking in the exhaust/mid box is still a (lower) risk, but front decore only viable on top if you've done the LPg conversation.
You pays your money and takes your chances, as they say. I don't think "don't buy an Elgrand" is a position I would take. Just look at the number of VW transporter type stuff that has lunched it's gearbox, turbo etc, had engine transplants, intergalactic mileage.... It's swings and roundabouts

 

[P4ddy]

That's why I no longer want a transporter. Lower risk is still a risk and it is a very expensive risk. My wife has weekly injections, we were told when I questioned there effectiveness they work in 99.9% of patients when administered fortnightly. I was dubious yet they insisted they would work. Nope she's now the only person who has them weekly being that 0.1%.
Front cat decore is a must imo from my readings & not just if going lpg, as you can opt for a new exhaust with rear cats. Either way get the fronts done and eliminate the risk not reduce it. As already proven on here, people's engines still go bang even with the rears done.

 

[dave132pne]

Anyone know where to get the rear cat decored in the North West?

 

[Gwilo365]

Anyone know where to get the rear cat decored in the North West?

Depends where in the north west. I hear that Pypers in Blackpool can do rears, they did a guy round the corner with an Elgrand who I told about the cat issues.
I can get their exact details and price if you want a day trip

 

[dave132pne]

Depends where in the north west. I hear that Pypers in Blackpool can do rears, they did a guy round the corner with an Elgrand who I told about the cat issues.
I can get their exact details and price if you want a day trip

Im Preston based and happy to travel to Blackpool (if I have to, PNE fan )

I would appreciate it very much if you could do that.

 

[Skid1769]

Having 're read this entire thread ( https://forum.elgrandoc.uk/threads/...and-the-do-not-remove-rear-cats-debate.18398/ ) again this morning here are my conclusions and the options available of which there are at least half a dozen. Rough costs are an estimate on people's postings throughout the forum. So please dont abuse me if some are slightly inaccurate!!! No agenda as I don't even own an e51 so completely impartial take on the matter.

Option 1.
Remove/decore the rear cats. Cost £100
Pros- cheap and easy. Van down time = a couple of hours.
Cons- not a 100% safe fix, and could still have future problems from front cats blocking themselves.

Option 2.
Remove/decore the front cats leaving the rears. Cost £400
Pros- eliminates chance of cat break down and blockage. Still a reasonable price.
Cons- more difficult to do, greater difficulty finding someone to carry out the work. Emissions feed back unknown. Van down time = 1 day

Option 3.
Remove/decore both front and rear cats and replace with aftermarket cats down stream. Cost £900
Pros- completely eliminates risk of old cats disintegrating. Healthy emmisions.
Cons- more expensive, very, very slim chance aftermarket cat could disintegrate in future. Van down time = 1 day.

Option 4.
Complete new stainless exhaust system with aftermarket cats. Cost £ 1200-1700
Pros- removes risk of original cat disintegration, sound lovely will last a long time.
Cons- more expensive. Very, very slim chance of cat failure. Van down time = 1 day

Option 5.
Lpg install. With full cat removal. Cost £2000+
Pros- eliminates any possibility of cat failure, cheaper fuel for future use. No emission worries at MOT as tested on lpg not petrol.
Cons- more expensive process, future lpg servicing costs, not all systems/setups are perfect causing possibility of other mechanical issues. Van down time = 3/4 days. Plus delivery/accommodation costs during process.

Option 6.
Carry on as you are with whatever process you've already done or not done.
Pros- live in a world of bliss and worry about what if's later. And enjoy life and your Elgrand.
Cons- your car could (But might not) breakdown at any moment. Expensive repair bill (£2.5k) or scrap value only.

Do with this what you will. The info is out there for anyone to read and make an informed decision on how, why, or what you want to do to extend the life of an Elgrand.
Don't think this discussion will ever go away, so long as people are still buying elgrands and not doing their homework on them.

Thats a very comprehensive list, many thanks for taking the time. One question, for anyone in the know, does any of these options have an effect when putting the van through an MOT..??

 

[dognero]

A lot also depends on the engine.
Miles, service, etc so there will be no 100% answer "yes"

Option 1. Lots do
Remove/decore the rear cats. Cost £100
Pros- cheap and easy. Van down time = a couple of hours.
Cons- not a 100% safe fix, and could still have future problems from front cats blocking themselves.

Option 2. Some do "Rears further away so take longer to warm up"
Remove/decore the front cats leaving the rears. Cost £400
Pros- eliminates chance of cat break down and blockage. Still a reasonable price.
Cons- more difficult to do, greater difficulty finding someone to carry out the work. Emissions feed back unknown. Van down time = 1 day

Option 3. Should do if decent cats are used "Rears further away so take longer to warm up"
Remove/decore both front and rear cats and replace with aftermarket cats down stream. Cost £900
Pros- completely eliminates risk of old cats disintegrating. Healthy emmisions.
Cons- more expensive, very, very slim chance aftermarket cat could disintegrate in future. Van down time = 1 day.

Option 4. Should do if decent cats are used
Complete new stainless exhaust system with aftermarket cats. Cost £ 1200-1700
Pros- removes risk of original cat disintegration, sound lovely will last a long time.
Cons- more expensive. Very, very slim chance of cat failure. Van down time = 1 day

Option 5. Should have no problems as long as it's tested as "LPG"
Lpg install. With full cat removal. Cost £2000+
Pros- eliminates any possibility of cat failure, cheaper fuel for future use. No emission worries at MOT as tested on lpg not petrol.
Cons- more expensive process, future lpg servicing costs, not all systems/setups are perfect causing possibility of other mechanical issues. Van down time = 3/4 days. Plus delivery/accommodation costs during process.

Option 6. If the cat's are in good condition then no reason not to pass.
Carry on as you are with whatever process you've already done or not done.
Pros- live in a world of bliss and worry about what if's later. And enjoy life and your Elgrand.
Cons- your car could (But might not) breakdown at any moment. Expensive repair bill (£2.5k) or scrap value only.


Hope this helps.
This is my opinion only

 

[Tonster]

Just did Option 1

 

[Chris J]

I've had a cost of £550 for new SS exhaust but I think this is with the primary cats left in ??? is this a decent option on a series 1?

 

[Martinbell]

I’ve got to get this sorted. 101k E51/3 09 plate.
The last garage I spoke to in Bristol said they wouldn’t do a decat as it was against the law. Sigh

 

[Jellyman]

Are there any cat issues on 3.5 e50's or is it just E51 onwards?

 

[Mrmick]

Having 're read this entire thread ( https://forum.elgrandoc.uk/threads/...and-the-do-not-remove-rear-cats-debate.18398/ ) again this morning here are my conclusions and the options available of which there are at least half a dozen. Rough costs are an estimate on people's postings throughout the forum. So please dont abuse me if some are slightly inaccurate!!! No agenda as I don't even own an e51 so completely impartial take on the matter.

Option 1.
Remove/decore the rear cats. Cost £100
Pros- cheap and easy. Van down time = a couple of hours.
Cons- not a 100% safe fix, and could still have future problems from front cats blocking themselves.

Option 2.
Remove/decore the front cats leaving the rears. Cost £400
Pros- eliminates chance of cat break down and blockage. Still a reasonable price.
Cons- more difficult to do, greater difficulty finding someone to carry out the work. Emissions feed back unknown. Van down time = 1 day

Option 3.
Remove/decore both front and rear cats and replace with aftermarket cats down stream. Cost £900
Pros- completely eliminates risk of old cats disintegrating. Healthy emmisions.
Cons- more expensive, very, very slim chance aftermarket cat could disintegrate in future. Van down time = 1 day.

Option 4.
Complete new stainless exhaust system with aftermarket cats. Cost £ 1200-1700
Pros- removes risk of original cat disintegration, sound lovely will last a long time.
Cons- more expensive. Very, very slim chance of cat failure. Van down time = 1 day

Option 5.
Lpg install. With full cat removal. Cost £2000+
Pros- eliminates any possibility of cat failure, cheaper fuel for future use. No emission worries at MOT as tested on lpg not petrol.
Cons- more expensive process, future lpg servicing costs, not all systems/setups are perfect causing possibility of other mechanical issues. Van down time = 3/4 days. Plus delivery/accommodation costs during process.

Option 6.
Carry on as you are with whatever process you've already done or not done.
Pros- live in a world of bliss and worry about what if's later. And enjoy life and your Elgrand.
Cons- your car could (But might not) breakdown at any moment. Expensive repair bill (£2.5k) or scrap value only.

Do with this what you will. The info is out there for anyone to read and make an informed decision on how, why, or what you want to do to extend the life of an Elgrand.
Don't think this discussion will ever go away, so long as people are still buying elgrands and not doing their homework on them.

 

[Mrmick]

I've had the rear cats replaced on my 2004 3.5 ( just reached 100k) with a decat set of pipes about 3 years ago and I'm getting a rattling sound which sounds like it might be from one of the front cats but I can't get underneath to try and find out if this is so.The rattling seems to die down above 2k rpm . Is there a way to check if indeed a cat is rattling and if so would it be worth having the front cats de cored and putting on the rears which were removed previously?
I'm supposed to be going to Wales this weekend and I'm a tad concerned about hitting the motorway .

 

[JohnK]

Are there any cat issues on 3.5 e50's or is it just E51 onwards?

E50s don't have the quad cat system so the answer is no.