WIP
Due to ongoing questions on buying a 3L Patrol, the following is a general overview of buying a ZD30DI based on the experiences of actual owners, the DI is not to be confused with the 2007 on CRD model which really has none of the engine issue that the early ZD30DI did, like any "make" if it hasn't been looked after then the chances of failure are higher.
Buying a used ZD30DI can be tricky, the early DI was a lottery, despite what you will hear from some they didn't all blow up, quite a few did (including mine) but many more survived and are currently running 300,000k+ (there is a thread in the archives on longevity, see link below), one thing to remember is that there are far more 3L ZD30's on the road than any other GU model. I would not buy a 3L between the years of 2000 and 2003 without factoring in a rebuild or crate engine replacement (note we didn't buy these things for their power, mostly we bought them for their fuel economy, so if you want to put another bigger engine in then do so). Once you get into 2003 the engine and ECU are much improved and later models even better. I would go out and buy a clean 2004/5 tomorrow no worries. The second point with the early model manuals was a weak 5th gear that had a habit of failing, this was rectified on models made after June 2002, apart from that the complete transmission system is bullet proof, often used by other makes in competition. My own vehicle is a 2000 DI that I bought new and serviced regularly and didn't thrash, it grenaded at the end of 2006 with 155,000k on it (not all do as mentioned), at the end of a 1000k work trip home, I had done around 7 of these that year where I jumped in the car at 4am and drove quickly 1000k to the work site, stayed a week and drove back home the same way, the repetition, high speed, cruise, load and not having an EGT gauge were big contributing factors. My 5th gear has been on the way out for some time but 296,000k later it's still hanging in there (edit: 5th finally let go at 320,000k).
The engine was rebuilt and the search was on to make the old girl as reliable as I possibly could, 12 years down the track she is stronger than ever.
You will hear a lot about NADS, which was originally a light hearted acronym for Nissan Anti Detonation System, the steps we took to prevent a blowup/grenade. Particularly for older ZD30’s, don’t for one moment think that fitting NADS will save your early ZD30 from cracking heads and melting pistons, if the base damage has already occurred, prolong it, yes, prevent it, no. The reasons a grenade happens are quite complicated and a vehicle can sit on the threshold of blowing up for very long periods of time and then one day the combination is right and it goes, but, rest assured for every ZD30 that blows up there are a myriad of it's Sisters that didn't, you only hear about the bad ones not the good ones, as said the reasons can be complicated. The base NADS I would do for a DI (or any diesel I bought for that matter) is a boost gauge and an Exhaust Gas Temperature (EGT) gauge, it's amazing the info about your engine you can glean from these gauges.
NOTE: We occasionally hear of repeat engine blowups, most of the time this is a direct result of skimping on the head in the rebuild following the original blowup, if you are going to rebuild, do not short change on the head, do it properly or it will come back to bite you later and you won't enjoy the years of trouble free motoring you should have.
The cooling system is beyond reproach, usually running between 84c and 90c, but like any modern system if it is not maintained there will be problems, it does not take rocket science or a lot of work to maintain them, good quality coolant and demineralised water changed occasionally (correct procedure is in the archives under maintenance) and there will be no problems. Mine runs normally between 84c and 87c and has just gone past 400,000k and coolant has been changed 4 times.
Also I would recommend having a read of this: NADS. So you have a ZD30 DI, here's "NADS" steps and logic with diagrams these are my recommendations based on my experiences, there are various options, but as said above there is a base I would do. Other useful information on maintenance and modifications are filed in here: ZD30DI TECHNICAL ARCHIVES FOR NEW AND OLD MEMBERS: Data/Mods/Maint/Gen Info.
Hope this helps prospective buyers. Further questions can be answered by posting in this subsection ZD30 DI Engine 3 Litre - Patrol 4x4 - Nissan Patrol Forum
Due to ongoing questions on buying a 3L Patrol, the following is a general overview of buying a ZD30DI based on the experiences of actual owners, the DI is not to be confused with the 2007 on CRD model which really has none of the engine issue that the early ZD30DI did, like any "make" if it hasn't been looked after then the chances of failure are higher.
Buying a used ZD30DI can be tricky, the early DI was a lottery, despite what you will hear from some they didn't all blow up, quite a few did (including mine) but many more survived and are currently running 300,000k+ (there is a thread in the archives on longevity, see link below), one thing to remember is that there are far more 3L ZD30's on the road than any other GU model. I would not buy a 3L between the years of 2000 and 2003 without factoring in a rebuild or crate engine replacement (note we didn't buy these things for their power, mostly we bought them for their fuel economy, so if you want to put another bigger engine in then do so). Once you get into 2003 the engine and ECU are much improved and later models even better. I would go out and buy a clean 2004/5 tomorrow no worries. The second point with the early model manuals was a weak 5th gear that had a habit of failing, this was rectified on models made after June 2002, apart from that the complete transmission system is bullet proof, often used by other makes in competition. My own vehicle is a 2000 DI that I bought new and serviced regularly and didn't thrash, it grenaded at the end of 2006 with 155,000k on it (not all do as mentioned), at the end of a 1000k work trip home, I had done around 7 of these that year where I jumped in the car at 4am and drove quickly 1000k to the work site, stayed a week and drove back home the same way, the repetition, high speed, cruise, load and not having an EGT gauge were big contributing factors. My 5th gear has been on the way out for some time but 296,000k later it's still hanging in there (edit: 5th finally let go at 320,000k).
The engine was rebuilt and the search was on to make the old girl as reliable as I possibly could, 12 years down the track she is stronger than ever.
You will hear a lot about NADS, which was originally a light hearted acronym for Nissan Anti Detonation System, the steps we took to prevent a blowup/grenade. Particularly for older ZD30’s, don’t for one moment think that fitting NADS will save your early ZD30 from cracking heads and melting pistons, if the base damage has already occurred, prolong it, yes, prevent it, no. The reasons a grenade happens are quite complicated and a vehicle can sit on the threshold of blowing up for very long periods of time and then one day the combination is right and it goes, but, rest assured for every ZD30 that blows up there are a myriad of it's Sisters that didn't, you only hear about the bad ones not the good ones, as said the reasons can be complicated. The base NADS I would do for a DI (or any diesel I bought for that matter) is a boost gauge and an Exhaust Gas Temperature (EGT) gauge, it's amazing the info about your engine you can glean from these gauges.
NOTE: We occasionally hear of repeat engine blowups, most of the time this is a direct result of skimping on the head in the rebuild following the original blowup, if you are going to rebuild, do not short change on the head, do it properly or it will come back to bite you later and you won't enjoy the years of trouble free motoring you should have.
The cooling system is beyond reproach, usually running between 84c and 90c, but like any modern system if it is not maintained there will be problems, it does not take rocket science or a lot of work to maintain them, good quality coolant and demineralised water changed occasionally (correct procedure is in the archives under maintenance) and there will be no problems. Mine runs normally between 84c and 87c and has just gone past 400,000k and coolant has been changed 4 times.
Also I would recommend having a read of this: NADS. So you have a ZD30 DI, here's "NADS" steps and logic with diagrams these are my recommendations based on my experiences, there are various options, but as said above there is a base I would do. Other useful information on maintenance and modifications are filed in here: ZD30DI TECHNICAL ARCHIVES FOR NEW AND OLD MEMBERS: Data/Mods/Maint/Gen Info.
Hope this helps prospective buyers. Further questions can be answered by posting in this subsection ZD30 DI Engine 3 Litre - Patrol 4x4 - Nissan Patrol Forum