Friday, Jan 20, 2006 at 22:56
Hi Everyone,
Hi Apwaddo,
You are 100% correct, but i was wanting more proof before i played my hand to end this scaremongering. I can now see that this is doing more damage than good as i know as
well as 99% of the people out there, THERE IS NO PROBLEM WITH THE NEWER ZD30 ENGINE. So do you want me to tell you what was wrong with your early cars?
Well here goes:
There is no longer a problem(when I say problem from now on I mean blowing up) with the ZD30 engine, we have examples in the UK with 200,000 plus
miles. Yes there was a combined problem in the early models, but it has been fixed.
I decided to take this route instead of adding to the top 1000 theories. Without some evidence and sound reasoning it would just become one of the many rumours.
So here goes my attempt at explaining the problem with the early ZD30 engine. Please remember like all mechanical devices there are always the exception to the rule, there is no black and white but a
grey area in the middle. I have based this theory on reading all the previous post for the last 3 years and then asking some questions, which were very strange.
I am also using my knowledge of Hi-Tech diesels put to use in areas where they really should not be used. The fact that Europeans have went through the change from low to high years ago a lot of what I am about to say is common knowledge but I was asking the wrong questions to begin with.
But lets get one thing straight, what I am about to propose is not the sole factor in the failure other events had to happen, and that has also came out on the survey. One question about this whole affair has always stood out as defying logic. WHY WAS THERE NO RECALL IN AUSTRALIA??? Why did Nissan ignore their largest market and change the engines in Europe where the patrol has no presence worth talking about.
Secondly, why the large variation in failure mileages ranging from 60,000 Km to over 200,000 Km. Now if I seen a spread like that in the work I certainly would not be blaming a single factor. If it had been say for example too small a diameter spray bar then the grouping of the failures would have been closer.
Now the strange one and the best clue yet. Why the increase in sump capacity??? Thats a strange one, there are no reports in any
forum or survey to suggest oil starvation, so why increase the sump capacity. There is no way Nissan who have been building 4x4’s for years would make a fundamental mistake of allowing the oil pickup to miss the oil due to extreme angles. So why the increase in sump capacity?
So the key to this is in Australia, you can bet any recall we got in Europe was prompted by the Australia failures, so again why no recall in Australia. If the recalls would work in Europe why would they not work in Australia. There is no way Nissan would have left that engine in Oz cars if they thought a recall would have fixed the problem, think about it! There most important market would have came first in the decision to recall.
Why have the other manufacturers held back their Hi-Tech diesels? For example the Diesel in the Toyota Prado(Landcruiser in the Uk) is an absolute cracker of an engine, 16 valves and all sorts of fancy stuff to make it run great but you get the ancient 2V engine.
Why the almost non existent rate of failures in Europe, there are isolated cases but no way of confirming if it was the same problem.
From most the reports the majority of early failures were from the utility companies etc. It stands to reason that they would be the first to notice a problem, they are normally used in extreme conditions and not always serviced by the book.
What we can learn from the utility failures were, poor service record and rough use. Big deal I hear you say a truck should be able to take that. Yes it should but not with oil that WAS NOT WORKING!!
I have experience with taking Hi-Tech Diesels to area where they are not sold locally and I know the simple precautions we need to take. So I will run through what we have to do and then I will tell you what its got to do with Australia.
Firstly lets look at the service interval in the UK for the ZD30 engine, its every 9000-
Miles which is 14500 Km or 1 Year. In fact most cars in the UK are now every 20,000
miles( 32,000Km) or 2 years.
The major part of this problem I believe is with the Diesel fuel used in Australia. After much hunting about I found out the following:
After December 2002 all Diesel fuel must have less than 500ppm(still very high) but before that anything up to 5000ppm was allowed. There was no major cut off date but a gradual reduction in Sulphur from about 2000 on, this was voluntary adopted by the big oil firms. The best figures I could find was they ranged from 5000ppm ---- 1200 ppm, that’s a very big span, but both figures are high. So until December 2002 you could have been filling your tank with any ppm between these two figures. So whats the big deal, sulphur only lubricates the seals and less sulphur means less pollution, hardly grounds for engine failure. WRONG WRONG WRONG.
There is one other side effect of sulphur which is not commonly know unless you venture out of Europe or run heavy industrial machinery in a high Sulphur area. The truck industry is also
well aware of this problem..
Lets look Diesel fuel specification in more detail as some aspects are important.
Four factors are important in Diesel
Sulphur Content is important for Lubricant and Lubricity.
Cetane number is important for Starting and power
Cloud point is important for waxing at low temperatures
Water contamination is important for Sedimenters and Filters
We are not really interested in the last two as I do not think they have any impact on this problem.
Just for completeness I will explain cetane, this is basically the parallel to octane rating in petrol. The higher the number the quicker the fuel ignites. A figure of 50 is about the European norm, some
places are as high as 56, basically it depends on how much gasoline is distilled off the crude oil. But this is not the cause of the problem but it can cause ignition-timing errors. A low cetane figure is 45 or under.
Now onto the sulphur issue, does it matter? Most definitely yes it does matter, it is crucial factor for the oil in your engine.
Lubrication contamination: This is the key factor, anything from 5000ppm and above is the danger level for a modern Diesel engine. Engine lubricating oil deterioration results from the use of high sulphur fuel. The contamination is sulphuric acid, where the sulphur combines with the water which is a product of combustion. There you have it a very nasty acid called sulphuric acid in you engine, this can cause engine corrosion, wear AND eventual
breakdown of the lubricant.
Ok so if you let the sulphuric acid build up then eventually your oil will break down and will be useless, it will still feel slippery but the all important additives will be gone, frightening thought. I will not go into specific details about oil brands but just say that the variation in oil brands ability to neutralise the acid is very large and is classed by a figure called TBN. But I do not want to get bogged down in fine details. But does this TBN number really matter, after all you don’t see fleets of bulldozers etc being wet-nursed over poor fuel, do you? You can bet your last dollar on that, yes they do. Caterpillar constantly monitors their oil using fuel sulphur analysers and residual TBN kits. Before you ask these are not really viable for an individual to own but it does show you the extent of the problem and that something must be done about it (ps caterpillars red flag goes up at 5000ppm).
So what do you do if you have a high sulphur fuel. The first thing you do is reduce the service interval. The rule of thumb for 5000ppm and above is reduce the interval by half for any engine. So we are 9000
miles in the UK that would make the interval 4500
miles (7000 Km) in Australia, and that would be the absolute maximum figure, any more than this you are sking for trouble unless you have a high TBN oil. If I was using a modern diesel which was my car in a area of 5000 ppm I would change every 7500 Km. Remember these modern Diesels are so dependent on the oil that it is critical that the oil remains effective. These modern diesels have tight tolerances, faster moving, higher stressed, this is why the oil is under such strain.
So it has already become apparent that the early cars were not regularly maintained, basically what this means is they were running about with severely reduced lubricant in their oil, not good. My Guess is some oils would have been almost useless after 7000 km depending on the TBN number. This would cause havoc with the internals, corrosion would be forming and the oil would not be lubricating correctly. In these cases the
breakdown of the oil would have been severe but that is not what caused the failures. It was only when an over boost situation occurred that pushed the engine which was already poorly lubricated and corroded over the edge. Remember oil is also a coolant so reduced oil function also reduces heat dissipation.
That would have been the first indication to Nissan that all was not
well with their engine. So what do you do in a situation like that, the first thing they could do is reduce their service interval. But who would buy a car with 7000Km service intervals when their competitors were almost double?
So here comes the question about the sump capacity, so why did Nissan increase the sump capacity. Simple, one other way to combat high sulphur fuel is to increase the amount of oil in the sump. Double the sump capacity for example, double the time taken for the sulphuric acid to break down the additives in the oil. If I was Nissan that would have been my first move as they knew this engine was not far away from handling this high sulphur as the fail rates were low. They were also
well aware that the Australian government was phasing in low sulphur fuel.
I also think at some point they did realise they could also have some internal engine problems that if fixed could help reduce the failures. These changes were enough to warrant a recall in Europe so obviously they found something but we will never know.
So why then was there not a recall in Australia? Again simple, they knew that with the high sulphur fuel their modifications would only buy time not solve the problem. So why put a new engine in, it was only going to suffer the same fate. They played the numbers game, they knew that the low sulphur diesel was just round the corner, they knew that after the modifications the fail rate would be lower, they just had to sit it out.
Basically they took the gamble to bring a high tech motor to Australia because 5000 ppm was borderline. So why all the variations in failure mileage, again it all depends on what ppm fuel you put in how often you changed your oil, what TBN you oil had, was it an ex
police car etc, whether you got over boost when the oil was useless. There are so many variables but the underlying cause was the oil was not lubricating correctly, internal fault(still unknown) and the internal corrosion all combined finished the job. Remember in Australia the early engines never had the “modification”, we will never know what this was but it looks like some lubrication issue and they had to put up with severe oil which further compounded this lubrication problem.
So basically what I am saying is the high sulphur in you fuel was breaking down the oil to such an extent that other smaller problems caused the engine to fail. The variation was due to varying oil changes, types of oil, quality of diesel and service interval. That is why we cannot find a single cause, there is none. And yes there might have been an internal fault or Nissan would not have re-called the European engines. Your poor quality fuel just exaggerated this internal problem and brought it to light but the modification was only part of the cure, we will never know for certain. Nissan brought a Hi-Tech diesel to Australia 2 years too early. Who knows with these internal changes and the work done to combat you high sulphur fuel, Nissan might have a very strong engine which could go on to surprise a few folk, but only time will tell.
This all got me thinking, what other countries have high sulphur fuel where they sell the patrol. The first country which stood out was Saudi Arabia where they have 10,000 ppm. So why were we not getting failures from there, again simple the 3.0 is not for sale in that country only the old 4.2 diesel. I started to
check through the high sulphur countries and guess what, the 3.0 is not for sale anywhere in the middle east which has high sulphur levels. I then decided to
check China with sulphur levels through the roof. You’ve guessed it no 3.0 for sale or 4.2D.
So fast forward to middle of 2002, the engines are of the modified type the ppm of the fuel is dropping gradually to 500 ppm. As far as I see it Nissan no longer has a problem as long as the modifications are correct, this will explain why we see no failures in Europe.
So on a final note, we will never know if there was any internal modification, as there are also rumours flying about that it was a bad batch which caused the re-call. So we need to take this out of the equation. So why all the Australian failures, why no failures in Europe where this engine is in everything from cars, trucks to buses. I hopefully have explained why I think this is.
But the problem has now gone, your Diesel has fell into line, and I believe it is to fall to 50ppm this year.
So I am going to cut the survey short as I always knew there was no problem with the ZD30. Nissans only fault was bringing a Hi-Tech Diesel to Australia two years too soon.
So yes I can see this is doing more damage that good. My last words on the subject are, I can guarantee that you will start to see some high mileage ZD30 engines soon now you diesel is sorted. From 2002 on there is absolutely nothing wrong with your engines, yes you might get the occasional failure which will get put down to this problem, but any engine can fail for thousands of reasons.
As for the people with 2000/01 models, I would not lose any sleep, I have trawled through many forums and I recon the fail rates are so tiny compared to the numbers sold, that is why it has not hit the national press.
Of course I cannot prove any of this but only time will tell, but in the meantime STOP bagging the newer models as yet they have proved to be very reliable.
Flame suit now going on!
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