E51 The E51 Catalytic Converter Problem

[LeStempy]

I think you're looking at around £1k

 

[arianaelgrande]

I think you're looking at around £1k

I haven't even taken delivery of mine yet but the rears are being decored by the dealer. Should this be enough? I don't know whether the car has had the recall or not yet so don't know if this makes a difference..

 

[LeStempy]

I haven't even taken delivery of mine yet but the rears are being decored by the dealer. Should this be enough? I don't know whether the car has had the recall or not yet so don't know if this makes a difference..

Ask for the chassis number then you can find out. A full replacement manifold back system would be the ultimate safeguard, but most are happy with just the secondary decat.

 

[Carl archer]

Could just get an exhaust shop to do a front cat back exhaust. Shouldn't cost more than 500. But dealer importing should be fixing that problem before handing it over. All imported elgrands by dealer should have replacement cats put in before bill of sale

 

[Pixelpoker]

replacing the whole exhaust from the manifolds back (move front cats back slightly, replace with higher flow sports cats and ditch rears) is IMO the only way for peace of mind.

...but i would say that as that's what i've had done


...just waiting for the flaming torches and pitchforks to arrive

 

[Carl archer]

I'm looking to do a straight through or have the front cata there but gut them out. Thinking a dual 2.5" all the way through

 

[Lpgc]

replacing the whole exhaust from the manifolds back (move front cats back slightly, replace with higher flow sports cats and ditch rears) is IMO the only way for peace of mind.

...but i would say that as that's what i've had done


...just waiting for the flaming torches and pitchforks to arrive

We're into the can of worms again...

Why say move front cats back slightly? I'd bet the answer is because some on forum reckon the front cats are too close to the engine exhaust ports... (which imo may be a contributing factor). But with that said it then begs the questions - How far back should these new front cats be fitted (so they won't suffer the same fate as original cats)? If the problem was just the location of original cats (too close to exhaust ports) then instead of fitting new cats why not just fit a spacer between manifold and original cats (if front cats seem in good condition)? Does the suggestion to replace front cats with aftermarket cats and also to fit aftermarket cats further back in the exhaust (further away from exhaust ports) reflect a belief that the problem is due to both the original cats being prone to failure (even if they were fitted further back) and being fitted too close or just one of these?

If an Elgrand will pass MOT running on petrol with front cats decored and rear cats still fitted, why buy new front cats when original front cats could be gutted (no parts to buy just labour for decoring front cats)?

For those running on LPG, if an Elgrand will pass MOT with all cats decored, decoring all of them (no parts to buy) may give more peace of mind than any other option. No cats at all fitted means absolutely no chance of any cat failure in any circumstances.. In contrast, an engine problem such as a stuck open petrol injector or badly broken PCV valve (or burning oil for any other reason e.g. valve stem seals etc) could cause any cat to fail, a new aftermarket cat may suffer the same fate as original spec cats under such conditions and maybe even in the same amount of time.

I still think decoring rear cats will save the majority of engines in the case front cats break up. I agree this isn't a total fix and know there's still a risk of front cats blocking themselves up (and I believe I was among the first to say so). But I don't think there's enough evidence yet to know how well aftermarket cats will fare in future, perhaps especially not if they're fitted as close to the engine as original cats were. For the amount of time people have been replacing front cats with aftermarket cats (this started relatively recently?) we probably wouldn't expect new original spec cats to have failed since being fitted either. The best 'sports cats' are the least restrictive to flow of exhaust gasses but no cat flows as well as a pipe with no internal restrictions or as well as a cat that has been gutted.

My personal level of confidence in an Elgrand not suffering cat problems over the long term goes something like this:

Totally original spec exhaust, all cats in place 30% confidence.
Decat rear cats 80% confidence
Decat front cats leaving rear cats in place 97% confidence
Fit aftermarket front cats leaving rear cats in place 87% confidence
Fit aftermarket front cats and gut rear cats 93% confidence
Decat all cats 100% confidence.

Those figures assume no engine problems, they could change very quickly if there are any engine problems involving excess oil or fuel getting into the exhaust system. The only figure that would not change in any circumstances is the decat all cats option.

 

[Pixelpoker]

We're into the can of worms again...

Why say move front cats back slightly? I'd bet the answer is because some on forum reckon the front cats are too close to the engine exhaust ports... (which imo may be a contributing factor). But with that said it then begs the questions - How far back should these new front cats be fitted (so they won't suffer the same fate as original cats)? If the problem was just the location of original cats (too close to exhaust ports) then instead of fitting new cats why not just fit a spacer between manifold and original cats (if front cats seem in good condition)? Does the suggestion to replace front cats with aftermarket cats and also to fit aftermarket cats further back in the exhaust (further away from exhaust ports) reflect a belief that the problem is due to both the original cats being prone to failure (even if they were fitted further back) and being fitted too close or just one of these?

If an Elgrand will pass MOT running on petrol with front cats decored and rear cats still fitted, why buy new front cats when original front cats could be gutted (no parts to buy just labour for decoring front cats)?

For those running on LPG, if an Elgrand will pass MOT with all cats decored, decoring all of them (no parts to buy) may give more peace of mind than any other option. No cats at all fitted means absolutely no chance of any cat failure in any circumstances.. In contrast, an engine problem such as a stuck open petrol injector or badly broken PCV valve (or burning oil for any other reason e.g. valve stem seals etc) could cause any cat to fail, a new aftermarket cat may suffer the same fate as original spec cats under such conditions and maybe even in the same amount of time.

I still think decoring rear cats will save the majority of engines in the case front cats break up. I agree this isn't a total fix and know there's still a risk of front cats blocking themselves up (and I believe I was among the first to say so). But I don't think there's enough evidence yet to know how well aftermarket cats will fare in future, perhaps especially not if they're fitted as close to the engine as original cats were. For the amount of time people have been replacing front cats with aftermarket cats (this started relatively recently?) we probably wouldn't expect new original spec cats to have failed since being fitted either. The best 'sports cats' are the least restrictive to flow of exhaust gasses but no cat flows as well as a pipe with no internal restrictions or as well as a cat that has been gutted.

My personal level of confidence in an Elgrand not suffering cat problems over the long term goes something like this:

Totally original spec exhaust, all cats in place 30% confidence.
Decat rear cats 80% confidence
Decat front cats leaving rear cats in place 97% confidence
Fit aftermarket front cats leaving rear cats in place 87% confidence
Fit aftermarket front cats and gut rear cats 93% confidence
Decat all cats 100% confidence.

Those figures assume no engine problems, they could change very quickly if there are any engine problems involving excess oil or fuel getting into the exhaust system. The only figure that would not change in any circumstances is the decat all cats option.

yep - everything you stated is valid.

My own decision making process is doing my own research and then deciding. Others will have a different point of view based on their own research/circumstances/preference.

I think we all agree tho that doing nothing and crossing your fingers is not advisable

 

[Steve Thompson]

We're into the can of worms again...

Why say move front cats back slightly? I'd bet the answer is because some on forum reckon the front cats are too close to the engine exhaust ports... (which imo may be a contributing factor). But with that said it then begs the questions - How far back should these new front cats be fitted (so they won't suffer the same fate as original cats)? If the problem was just the location of original cats (too close to exhaust ports) then instead of fitting new cats why not just fit a spacer between manifold and original cats (if front cats seem in good condition)? Does the suggestion to replace front cats with aftermarket cats and also to fit aftermarket cats further back in the exhaust (further away from exhaust ports) reflect a belief that the problem is due to both the original cats being prone to failure (even if they were fitted further back) and being fitted too close or just one of these?

If an Elgrand will pass MOT running on petrol with front cats decored and rear cats still fitted, why buy new front cats when original front cats could be gutted (no parts to buy just labour for decoring front cats)?

For those running on LPG, if an Elgrand will pass MOT with all cats decored, decoring all of them (no parts to buy) may give more peace of mind than any other option. No cats at all fitted means absolutely no chance of any cat failure in any circumstances.. In contrast, an engine problem such as a stuck open petrol injector or badly broken PCV valve (or burning oil for any other reason e.g. valve stem seals etc) could cause any cat to fail, a new aftermarket cat may suffer the same fate as original spec cats under such conditions and maybe even in the same amount of time.

I still think decoring rear cats will save the majority of engines in the case front cats break up. I agree this isn't a total fix and know there's still a risk of front cats blocking themselves up (and I believe I was among the first to say so). But I don't think there's enough evidence yet to know how well aftermarket cats will fare in future, perhaps especially not if they're fitted as close to the engine as original cats were. For the amount of time people have been replacing front cats with aftermarket cats (this started relatively recently?) we probably wouldn't expect new original spec cats to have failed since being fitted either. The best 'sports cats' are the least restrictive to flow of exhaust gasses but no cat flows as well as a pipe with no internal restrictions or as well as a cat that has been gutted.

My personal level of confidence in an Elgrand not suffering cat problems over the long term goes something like this:

Totally original spec exhaust, all cats in place 30% confidence.
Decat rear cats 80% confidence
Decat front cats leaving rear cats in place 97% confidence
Fit aftermarket front cats leaving rear cats in place 87% confidence
Fit aftermarket front cats and gut rear cats 93% confidence
Decat all cats 100% confidence.

Those figures assume no engine problems, they could change very quickly if there are any engine problems involving excess oil or fuel getting into the exhaust system. The only figure that would not change in any circumstances is the decat all cats option.

Nice summary Simon.
But my take is:-
The cats are a consumable.
Life is 10 years/100kmiles with a good setup.
The Elgrands are not a good setup.
Get them out and gone ASAP.
Stop fukin about with a few hundred quid.

 

[LeStempy]

My ultimate solution would be to decore the fronts and put in a new set of rears, but for the moment I'm sticking with the rears decored and fronts still in place.

 

[Lpgc]

My ultimate solution would be to decore the fronts and put in a new set of rears, but for the moment I'm sticking with the rears decored and fronts still in place.

Sounds like a plan for those running on petrol. Never known the rears to fail (except of course when the entrance has been blocked by debris from broken front cats) but the number of Elgrands with fronts decored and rears still in place will be small... We don't know if rears will be more likely to fail if fronts have been decored, would expect rears to be doing a lot more work with fronts gone. There's nothing to suggest a problem with the rears, just that we don't know, and as Steve says cats don't last forever.

 

[Highway Dave]

I have no popcorn
I also have no rear cats

 

[Kenzie (Mary Poppins)]

I'm wanting all 4 chopped off

 

[LeStempy]

Yeah, open headers with side exit and flames.

 

[Lpgc]

I am currently starting on removal of front cats on my latest (black) Elgrand.
The plan is to remove, decore and refit them at the same time as LPG conversion.

 

[MHd]

Hi guys, I'm having a nightmare trying to get the de-core done on my E51. I had it in with someone this morning and they did a no show and have messed me around to be honest for the last couple of weeks.

Is there anyone on here that comes out to do them that could be fairly local to me? Obviously will pay etc.

I'm close to Cannock and already have the 4 new Gaskets to replace the old ones with. I would have done it myself but don't really have the best gear to get the bolts off as they will probably need heating up to get off.

I don't mind travelling to someone either if they're fairly close?

Cheers,
Matt

 

[Lpgc]

To decore the rear cats one of them has to be cut open (to access the innards) then welded back up... A mobile guy would have to bring a welder.
Wouldn't normally heat the bolts up, if they're so corroded they won't come off they either shear or round-off. If they shear you'd just cut/knock the studs out and refit with nut and bolt, if they round off you'd cut the nut off then fit nut and bolt.

I doubt anyone would come out to decore front cats at yours. I recently decored front cats on the drive (to show how it can be done on the drive), there's a lot of work involved, here's a thread I did about it https://forum.elgrandoc.uk/threads/front-cats-decore.21762/

 

[MHd]

To decore the rear cats one of them has to be cut open (to access the innards) then welded back up... A mobile guy would have to bring a welder.
Wouldn't normally heat the bolts up, if they're so corroded they won't come off they either shear or round-off. If they shear you'd just cut/knock the studs out and refit with nut and bolt, if they round off you'd cut the nut off then fit nut and bolt.

I doubt anyone would come out to decore front cats at yours. I recently decored front cats on the drive (to show how it can be done on the drive), there's a lot of work involved, here's a thread I did about it https://forum.elgrandoc.uk/threads/front-cats-decore.21762/

Thanks for the info.

I get that it can be a bit niggly but I'm only interested in the two rear cats.

I've had a look under the car and to be honest it seems that the bots are very accessible for the rear cats to be removed without having to remove any shielding etc, maybe this isn't the case though?

 

[LeStempy]

Thanks for the info.

I get that it can be a bit niggly but I'm only interested in the two rear cats.

I've had a look under the car and to be honest it seems that the bots are very accessible for the rear cats to be removed without having to remove any shielding etc, maybe this isn't the case though?

@Winchester does a postal exchange service.

 

[Lpgc]

Thanks for the info.

I get that it can be a bit niggly but I'm only interested in the two rear cats.

I've had a look under the car and to be honest it seems that the bots are very accessible for the rear cats to be removed without having to remove any shielding etc, maybe this isn't the case though?

It can help access (to the drivers side downpipe to exhaust/rear cat section flange) to lower the middle area plastic undertray at the drivers side but it's very easy to do that, you don't have to remove the full undertray.

@Winchester does a postal exchange service.

Ahh yes! If you exchanged rear sections through Winchester no welding would be necessary.