Wednesday, Jul 28, 2004 at 22:04
Hi guys,
My understanding of the blown motors is that its virtually always been a holed/melted piston on 3/4 cylinder. I believe its a lack of cooling from the oil and that the series III had larger oil galleries, 2nd oil pickup point and more oil cooling sprays plus more sensors for the ECU. Also, pistons 3/4 get less natural air cooling, hence the reason they go first (or could be to do with the oil gallery design?)
Running lean on a diesel decreases piston temps, the opposite of a petrol vehicle so I don't think a simple ECU fix would help. I run a Dtronic on mine and it gets the same, if not better, fuel consumption while giving a really noticeable power boost, particularly at low revs.
I have searched widely on the net and have yet to come across a single proven case of series III engine failures. There are some reports of them, but NEVER from the owner, always someones mates uncles brothers dogs best friends aunty and when pressed for details, do not even know for sure if its a series II or III. But there are many first hand accounts of series II failure (too many!!!). I obvioulsy have not heard of a series III Dtronic blowing (if mine ever does, you will all be the first to know, followed very closley by Nissan!!!). There are many series III now with 200,000kms+ on them, a good sign for sure that the problems have been fixed.
The most common series III fault I have found to date is the EGR valve. It can seize and this results in the motor shutting down. However, I think thats an ECU shutdown to prevent running with a seized EGR as the volume of exhaust gas should not stop the motor from running at all. But I have not had this confirmed. Also, the type of oil you use can affect its operation. The latest CI oils are designed specifically for EGR diesels. I believe they somehow assist in lubricating the EGR valve, but early CI oils suffered from oil usage between service intervals (probably vaporised some oil to lube the EGR valve?)
The biggest "problem" with this motor (and virtually all modern diesels) is the multitude of sensors that can stop it and all you get is a single engine fault light. Often the ECU will shut the engine down, yet it is quite capable of running abeit with a loss of power. Probably Nissan saving on engine damage (warranty cost!!!).
Cheers
Captain
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