E51 The E51 Catalytic Converter Problem

[LeStempy]

I brought cat replacement pipes and it took me an hour to do both.

 

[MHd]

I brought cat replacement pipes and it took me an hour to do both.

Maybe that's the way to go?

I just thought them pipes were pretty pricey to get hold of on ebay for the sake of 100 quid or so to get them bashed out

Did you have much trouble getting the bolts off?

 

[LeStempy]

Maybe that's the way to go?

I just thought them pipes were pretty pricey to get hold of on ebay for the sake of 100 quid or so to get them bashed out

Did you have much trouble getting the bolts off?

No trouble. Just a set of spanners and a bit of ACF 50.

 

[Lpgc]

I've done a lot of rear cat decores, they usually come off no problem but I've had to cut nuts off a few.

 

[Winchester]

Maybe that's the way to go?

I just thought them pipes were pretty pricey to get hold of on ebay for the sake of 100 quid or so to get them bashed out

Did you have much trouble getting the bolts off?

For £100 you could have a set of my refurbished factory de-cored rear cats delivered to your door, see my ad in the trade section.
Regards Adrian

 

[MHd]

For £100 you could have a set of my refurbished factory de-cored rear cats delivered to your door, see my ad in the trade section.
Regards Adrian

Awesome.

Sounds like this is the best way to go, i'll have a look now.

@Winchester I've just sent you a private msg about this...

 

[JimR]

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

Try Stuart Spencer Autos in Dudley Port ( Between Great Bridge andDudley roughly 35 mins from you),,they deal in Elgrands and they did mine no problems

 

[Aranadin]

Hi everyone, I've just been chatting to my father about getting his cats either de-cored or replaced, the question is, does anybody know of someone who can do this for him in the Middlesbrough area? Thanks.

 

[Carl archer]

Might be best to git up an exhaust shop and find out how much to do a front cat back system on the beast

 

[bunnykins]

THIS IS NOT FORUM LORE. THIS IS NOT A MYTH. THERE HAVE BEEN MANY DOCUMENTED INCIDENTS WHERE OWNERS HAVE HAD THEIR ENGINE BLOW UP BECAUSE OF THIS ISSUE. YOU HAVE BEEN WARNED.

CHECK OUT THIS THREAD FOR PROOF

LIST OF AFFECTED MEMBERS

The problem

A widely known issue with the Nissan Elgrand E51 is that the rear cats get blocked causing catastrophic
damage to the engine.

The problem starts with the fact that the E51 has a QUAD CAT SYSTEM. This means there is a PRIMARY and a SECONDARY catalytic converter on EACH BANK of the V6 engine.

The PRIMARY cats are the ROOT CAUSE of problem. Through use, after heating up and cooling down, they start to deteriorate. This happens with ANY ceramic catalytic converter when they reach the end of the their life. As the PRIMARY cats starts to break down and fall apart, the debris is pushed back through the exhaust. At this point, they come into contact with the SECONDARY cats, which creates a blockage.

As more and more of the PRIMARY falls apart, the blockage will prevent any exhaust gasses getting out. The exhaust gases (and dust particles) then build up pressure and go to the only place they can, back into the engine. It doesn't take a mechanic to know that if you put exhaust gas mixed with catalytic converter debris back into an engine, it's not going to last long.

So, that covers the problem, what can you do about it?

There are 3 main options.

1/ DECORE the SECONDARY CATS. This is a simple process. You remove the secondary cats, cut an opening in the top, smash the internals out, weld the opening shut again and re-fit them. This removes the point at which the debris from the PRIMARY cats will get stuck creating a blockage. The debris is just pushed out the back of the exhaust. THIS IS NOT A 100% SAFE OPTION. Debris can still trap itself within the primary cat or the mid box of the exhaust. Although removing the rear cars reduces the chances of catastrophic failure exponentially... it will not 100% stop it from happening.

2/ Remove the SECONDARY CATS. Same principle as option 1, but you remove the cats altogether and replace with a straight through pipe. This is more costly than option 1, BUT what it means is that when it comes to MOT time, you still have the cats to fit to the vehicle if there are ever any issues. As with option 1, this is not a 100% failsafe option for the same reason outlined above.

3/ By far the most expensive option, but still an availability if you have the funds to allow it. Replace the WHOLE system (Manifold back) with a custom made stainless exhaust with single stage, high flow metal sports cat. Dig deep for this one, but the noise will be worth it - This option will 100% remove the risk of damage caused by the standard catalytic converter failure problem.

REGARDLESS OF WHAT METHOD YOU CHOOSE - YOU MUST CHECK FOR DEBRIS FROM FAILING FRONT CATS AND INSPECT THEM BEFORE YOU MOVE FORWARD. IF THEY HAVE ALREADY STARTED TO DETERIORATE, YOU SHOULD HAVE THE WHOLE SYSTEM REPLACED AND THE ENGINE HEALTH CHECKED BY A PROFESSIONAL.​

But what about.......?

You will fail an MOT if you remove the rear cats and the tester knows they should be there. So if you do fit straight through pipes, keep the cats and then you can fit them again at a later date if you need to.
If you go for option 1, make sure the access hole is cut in the top of the cat so that the head shield will cover the weld when it's sealed up again. If the hole is on the bottom, and the tester can see that they have been tampered with, he'll fail it.

Emissions are NOT affected by removal of the secondary cats. They are only part of the system due to the strict "cold starting" emissions policies in Japan. In the UK the emissions test is done on a warm engine, and therefore the secondary cats serve ZERO purpose.

Is this legal?

I don't know what PC Plod can do about you removing/modifying the cats. But, if you tell an MOT tester that you have modified the cats in any way, and it fails, then technically the car is not road worthy. We know this is bollocks. It'll still pass the emissions test, it will still drive perfectly OK, and you have removed the risk of having your engine blow up when belting down the motorway at no more than 70 (of course).

The choice on what you do is up to you. Keep them if you want. But then every time you drive your E51 you will be wondering when the engine is going to blow up. I know from a personal point of view, I'd rather take the risk with the MOT tester than have catastrophic engine failure and a £4500 engine rebuild bill.

I heard about a Recall for this problem!?

The recall has NOTHING to do with this problem. All it will do is prolong the inevitable. The recall was put out to adjust the fuelling. If your car is subject to the recall, the engine map was putting too much fuel into the engine. This meant that excess fuel was getting blown out of the engine following combustion and then igniting in the exhaust system due to the heat. This meant that the exhaust was getting a lot hotter than it should causing premature deterioration of the primary cats.
With the recall in place, the engine will not overfuel... but it does not mean that the primary cats will not start to disintegrate over time.

There have been at least 2 instances that I know of where a car that was NOT on the recall list has had the engine fail because of blocked cats.

Why does this need doing?

Cars built for EU and UK roads are designed with the climate in mind. Therefore, as part of the manufacture process, there are treatments applied to the bare metal to prevent the chassis corroding. JDM cars are NOT done, because the climate in Japan is very different to ours.

The underseal is required to ensure that your car doesn't turn into a pile of rust over the winter. More importantly, because you are doing this AFTERMARKET, it is something that is seen as temporary, not permanent. The products applied will, over time, wear off or get damaged thus leaving untreated metal to come into contact with salt and moisture.

The better the product you use, the longer it's life. There may even be products out there that come with a "life of the car guarantee"... but I'm sure they'll cost more than £400!

With that in mind, discuss the options available with the garage you chose for your underseal and discuss repeat applications and how often they will be required. If they want your continued business, they will offer all options and tailor the service to your requirements and budget.

Now I'm a bit nervous...not sure how I'm going to decide what to do about mine especially as I'm unlikely to be able to do this stuff myself. Will re-read and talk to the dealer....
Update: Dealer says option #1 or #2 is up time to choose but comes out around £330 for each.

 

[bunnykins]

Now I'm a bit nervous...not sure how I'm going to decide what to do about mine especially as I'm unlikely to be able to do this stuff myself. Will re-read and talk to the dealer....
Update: Dealer says option #1 or #2 is up time to choose but comes out around £330 for each.

Still trawling through the posts on this thread. Looks like it will pay me to shop around

 

[LeStempy]

Now I'm a bit nervous...not sure how I'm going to decide what to do about mine especially as I'm unlikely to be able to do this stuff myself. Will re-read and talk to the dealer....
Update: Dealer says option #1 or #2 is up time to choose but comes out around £330 for each.

Still trawling through the posts on this thread. Looks like it will pay me to shop around

If you were to take advantage of the @Winchester postal exchange service it should take no longer than an hour for any competent mechanic to swap them out.

 

[bunnykins]

If you were to take advantage of the @Winchester postal exchange service it should take no longer than an hour for any competent mechanic to swap them out.

Thank you for your suggestion Stempyuno. Much appreciated

 

[Darlaur]

Hi all.
Can anyone tell me where I can get a stainless steel sports exhaust fitted to my E51, will this eliminate the cat problem, will I have any issues with the MOT regarding this mod? South Wales area.
Many thanks.

 

[LeStempy]

Find your nearest Powerflow dealer.

 

[Pixelpoker]

Hi all.
Can anyone tell me where I can get a stainless steel sports exhaust fitted to my E51, will this eliminate the cat problem, will I have any issues with the MOT regarding this mod? South Wales area.
Many thanks.

depends on how much you want to spend. Avoid kwikfit and other national chains would be my advice. Like most things in life you pay peanuts - get monkeys.

For a decent one that replaces the exhaust from the manifold back - engine>manifold>pipe>sports cats>pipe>centre box>pipe>backbox>exhaust tips (fully purge welded and good sports cats) you'd be looking around £1500+ i reckon.

As for MOT, have a search on here. Several of us have had similar to what i mentioned above (me included) and no issues with MOT's etc

 

[Darlaur]

depends on how much you want to spend. Avoid kwikfit and other national chains would be my advice. Like most things in life you pay peanuts - get monkeys.

For a decent one that replaces the exhaust from the manifold back - engine>manifold>pipe>sports cats>pipe>centre box>pipe>backbox>exhaust tips (fully purge welded and good sports cats) you'd be looking around £1500+ i reckon.

As for MOT, have a search on here. Several of us have had similar to what i mentioned above (me included) and no issues with MOT's etc

Thank you.

 

[Pixelpoker]

Thank you.

try asking @Lisa-Marie or @Elementian (both wales based) for more local knowledge...or try calling colin price (welsh importer) to see if he has any advice

 

[Darlaur]

try asking @Lisa-Marie or @Elementian (both wales based) for more local knowledge...or try calling colin price (welsh importer) to see if he has any advice

Thank you

 

[Steve Thompson]

Hi all.
Can anyone tell me where I can get a stainless steel sports exhaust fitted to my E51, will this eliminate the cat problem, will I have any issues with the MOT regarding this mod? South Wales area.
Many thanks.

There are a few clear options now.
For me - I chose front cat decore from Paul at Powerflow Cardiff (£240).
Plus LPG fitted by Simon @Lpgc
Now proven to be quite a good route.