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E51 The E51 Catalytic Converter Problem

There's some on eBay. They sell each side separately but they are uk based it says.
 
Thanks but I can only seem to find the Australian one's
 
Thanks found some now https://www.ebay.co.uk/itm/FITS-Nis...=item1cbe8844cd:g:zQYAAOSwfZhXNKM1:rk:14:pf:0
 
Karl said:
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 problem. Through use, after heating up and cooling down, they start to deteriorate. This happens with ANY 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 2 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.

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.

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.
Click to expand...

AMAZING thank you! I’m sure you’ve helped hundreds of us 😊
 
Karl said:
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 problem. Through use, after heating up and cooling down, they start to deteriorate. This happens with ANY 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 2 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.

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.

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.
Click to expand...
Good
 
Single most important mod...........done! ;)
 
Does anyone know the part number for the gaskets eitherside of the cats as I’m going to remove them at the weekend to sort out
 
Mightmetro said:
Does anyone know the part number for the gaskets eitherside of the cats as I’m going to remove them at the weekend to sort out
Click to expand...

The factory multi layer metal gaskets are good to re-use and better quality than the aftermarket ones you can get. I re-fit them with a thin smear of exhaust gasket paste on each side. Never had a problem.
 
Winchester said:
The factory multi layer metal gaskets are good to re-use and better quality than the aftermarket ones you can get. I re-fit them with a thin smear of exhaust gasket paste on each side. Never had a problem.
Click to expand...
Yep, reused mine and all good, they may look as if there are slight gaps in the layers but don't worry, the seal is at the centre
 
Fab thanks, just removed mine and they were still standard even though the previous owner said they had been done although he was a little confused between front and rear cats. No debris in either but better safe than sorry. Smashed all the middles out. Just need to find a local welder to weld the top flap back on 👍🏻
 
After owning my E51 for 2 and half years I decided to do the cats today. Right job getting them off on the driveway. All the nuts and bolts were corroded and every one needed plenty of heat before they came off (should have done them when I'd bought it). Cats looked clean inside before smashing them out though. Front cats must still be OK. Going to refit tomorrow with old gaskets and some paste. Done approx 85,000mls.
 
should this be reported to your INS as a mod
 
Probably. But where do you stop? Would you report different, better tyres. Fitting better bulbs - L.E.D for example. Better brake pads - E.B.C. for example. Braided hoses. Different radio. The list could go on. This mod isn't for performance, but maintenance. I would doubt any insurance company would remove the exhausts to inspect the cats, especially if it looks standard.
 
Lpgc said:
My engine is seized now because my cats blogged the exhaust while I was towing my caravan going on holiday.

A few people from forum already know about it happening to me too, as I spoke to them on the phone while on holiday.
I told them I'd write a full report about it on this forum at some point after my return from holiday, I've been back from holiday a few weeks now but during those weeks I've been very busy (converting Elgrands and other vehicles), helping to rescue LPGforum, helping someone move house, and I had to go back (to Cornwall) to collect my caravan.... So I haven't had much time to write the sort of lengthy detailed post that people have to come expect from me (even on lesser matters) on this important matter.

But it's about time I wrote something even if it's not as lengthy or detailed as I intended.

The gist of it is that I didn't have time to decore my own Elgrand's cats before I went on holiday to Cornwall fully loaded with people and with my 26ft Caravan on tow also fully loaded. Towing uphill on the A30 up Bodmin Moor I felt a sudden decrease in engine power (as I've said on this thread before people should expect to feel when their cats go) and recognised that this was probably due to the cats having failed, so I pulled into the first layby and scanned the vehicle OBD for engine problem codes. There were error OBD problem codes for camshaft position sensors, this confused the matter because cam sensor issues could also mean lower engine power, so I phoned a certain guru on this site for a second opinion before taking the exhaust off (which would have meant sending someone who was following us in another car with a baby on board into the nearest town to buy the necessary tools). Guru reckoned it unlikely to be the cats that were the problem, I should try cleaning the cam sensors and see how it drove/towed then. So perhaps against my own judgement I did continue on the journey to see how it went after cleaning cam sensors but after cleaning the cam sensors the engine was still down on power. Now that I'd connected my laptop to get more detailed information (from the LPG system readings) than any code reader could provide (at least regards fuelling) I could see that the problem was on the passenger side bank of engine cylinders. So, I didn't drive much further (just a couple of miles but with the engine struggling) before pulling into the nearest layby and phoning the RAC. RAC man number 1 came out, I told him about the problem with Elgrand cats and that it seemed very likely to me that this was the problem. He listened but even though he couldn't find any problem himself (and his OBD scanner gear didn't even work on the Elgrand whereas I'd got a £30 JOBD scanner on board that did work on the Elgrand which told me about the cam sensor issue, which I told him about), he didn't seem to believe it would be cats that were the problem and seemed to be in a rush to get away. He told me that my RAC cover on;y covered the car, not the caravan, and that if I wanted the caravan shifting to Newquay from here (30 miles away) it would cost me about £500 by one of their sub-contractors. He recommended I continue to drive 'now the engine has cooled down a bit' and told me 'we are right on the top of Bodmin Moor here so its all downhill to Newquay' and 'see how it goes on the downhill stretch you should be OK to Newquay from here'. This time, very much against my better judgement and I have to question myself on why I did it... I drove a few more miles towing the caravan and it felt the same but getting worse. RAC man number 1 was still following me at this point so I pulled over half onto the grass verge and RAC man stopped behind me. At this point I insisted he loaned me a hammer and chisel so that I could knock a hole in my exhaust because he wasn't allowed to do anything like that due to Elf-n-safety. I even had to sign a disclaimer form before he'd loan me the hammer and chisel and then another form to say I'd decided to do something against his advice. I knocked a hole in the exhaust just in front of the passenger side rear cat and loads of cat material that must have come from the front cats breaking up came out, so I had to knock a second hole in it much further up the pipe closer to the front cat just to make the hole in front of the broken cat material that was clogging the rear cat and it's feed pipe. RAC man was very surprised to see the cat material come out of the hole and, really, at this point we both knew that him advising me to drive further might have caused me some severe problems and that I was daft to have followed his advice... This time starting the engine after knocking the holes in the exhaust I could see on my laptop readings that the engine seemed much happier, was drawing more vacuum and it revved more freely... But the exhaust was now rather loud with the holes I'd knocked it it! We all set off again and this time the engine pulled properly just as it did before the problems had started. I thought problem nearly solved I'll just get an exhaust place in Newquay to decat and fix the holes in the exhaust while we're on holiday. RAC man who was following phoned me and said 'You seem to be OK now so I'll leave you to it'. I said 'OK mate cheers'. But 10 miles further down the road and after the RAC man had left me the same lack of power problem re-occurred and seemed worse than ever. This time it couldn't be a problem with the passenger side cat, if it were a cat problem it could only be with the drivers side cats (which I hadn't knocked a hole in). At this point my laptop battery had died so I didn't have the diagnostic window that the LPG software had given me earlier. And this time the engine started to overheat and then the oil warning light came on while I was going up another steep hill (after the RAC man had said it was all downhill to Newquay 10 miles earlier). I pulled over again in as safe a spot I could manage/make it to (but still dangerous especially with the volume of traffic) and called RAC out again. RAC man number 2 came out, he had an outline description of what had happened before from the RAC but I filled him in with the details. Told him I wanted the car and caravan shifting to Newquay but there was no way I was paying an RAC subcontractor £500 to shift the caravan, said he must know some recovery garages in the area please phone them instead of the £500 RAC subcons. He phoned a recovery garage for me, they didn't have a lorry big enough to put the caravan on but came out with a lorry and a van, the van pulled the caravan, the Elgrand was loaded onto the lorry.. These were good lads and I'd use them again if I needed a tow in Cornwall. £150+Vat for shifting a car and caravan 15 miles using two of their vehicles and 2 guys so a reasonable price too. Arrived at camp site 5 hours later than expected, a bit tired, no working car and a broken Elgrand. Got set up on the campsite and next day while everyone else went into Newquay I set about trying to diagnose and fix the Elgrand. I went to St Austell in the other car that went on holiday with us and bought loads of tools, engine oil, etc, and then unbolted the other side exhaust (drivers side the side I hadn't knocked holes in). I hoped the more recent problems (after the apparent fix) would be fixed when I removed the drivers side exhaust but the engine still pulled the same. Going out of the campsite there's a very steep hill at each side, I started going up a hill and the engine suddenly seized dead. I rolled backwards down the hill all the way back into to the car park of the camp site which is where the Elgrand stayed until I more recently went back to Cornwall (in my Merc ML) to get the Elgrand shifted back home. But at least I got a couple more days in Cornwall out of the misfortune lol!

When I have this engine out I'll strip it to see what damage the cat problem led to. Would be interesting to hear/read if other people have stripped engines that failed following cat problems and what damage they found... Perhaps this engine could be repaired (I won't know until I've stripped it) but I'm thinking it'll probably be just as easy just to get another engine for it.
Click to expand...


Did you get it fixed in the end? how serious was it? did you get a new engine?
 
Whaley said:
Did you get it fixed in the end? how serious was it? did you get a new engine?
Click to expand...

He has a replacement engine waiting to go in.
 
Lpgc said:
That's right, cheers Ian.
When I've swapped engines I'll strip the old one (when I get time) and take pics of damage etc.
Click to expand...

Shortest reply ever!

Joking aside, I would expect to see scoring of the bores and pistons, and severe wear on piston rings. Valves may be damaged too. If an engine could be fixed by a re-hone plus maybe new rings and pistons it could be doable. but the oil pump could be trashed too. Hopefully the oil filter would have done its job and saved other parts like camshaft, crankshaft etc.
 
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