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The 3.0 GU Engine

Posted: 24 Jul 2016 12:04
by Johann 1984
Morning Gentlemen,

Could someone assist me with info with regards to the 3.0 GU engine? I read on the Aussie forums that there is a generation 1, 2 , 3 & 4 derivative on this engine. Generation 1 being the culprit (according to the Aussies) that were mostly problematic. Then there were generation 2 (some problems), 3 and then finally 4 which I understand is a common-rail diesel. Is this true? And if so, from which year onward were the common rails? I have a 2013 3.0 GU. To which of the above does it belong?

My engine has now done 84 000 km's. It is not brand new anymore and on the 18th of July 2016 the 3 year Nissan factory expired. The vehicle is now 3 years old. I have been told by a fellow traveler in Botswana, whilst staying over at Elephant Sands for the evening, that I should speak to a mechanic about having the (catalytic converter / emission reduction unit?) removed as it blows dirty fumes back into the engine heating piston number 4 and a little also nr 3 (his claims not mine). I went to Nissan in Kimberley (Northern Cape) to ask them to do it and I got the reply from the technician was that it would reduce the engine reliability and I should not tamper with it at all. I then phoned a very friendly gentleman at Imperial Nissan in Menlyn Pretoria (who used to always service my patrol when I still lived there) and he assured me that 'die 3 liter gee niks k#k nie meneer' (his exact words). So, can someone perhaps just tell me what the process entails and what the consequences of it will be? If someone knows, it would be nice.

Once again, the vehicle now has 84 000 km on it. What concerns me is that I have to add about a point of oil every 3 - 4 months (a point being a coke size can at shell). Is this normal? it has been like this since I bought the vehicle. I service my Patrol @ Nissan every 15 000 km as required by the manufacturer. My previous 4x4, a Nissan Hardbody 2.5TDi didn't require a single oil refill between services in the 70 000 km that I drove it. I found that 2.5TDi (YD25) engine the best I have ever experienced of all vehicles I have ever driven.

Any thoughts? Has the 2013 ZD30's shown any issues? I know an abused engine will always give issues, but mine is used 'normally'.

Regards

Re: The 3.0 GU Engine

Posted: 24 Jul 2016 14:09
by JoshJ
Hi Johann,

If you open your bonnet and it looks lik the picture below you have a common rail gen4. This is the good one. I have one. Only done 56 000km up to date. I will suggest removing the CAT's. I replaced my std exaust with 3 inch down pipe and freeflow. It reduced EGT's and increased torqeu by 60nm. I will stil suggest that you install a full madman system. This wil help you monitor everything on the car. :mytwocents:
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Re: The 3.0 GU Engine

Posted: 24 Jul 2016 15:26
by Tinus lotz
Jip josh has a great machine there also get rid of your egr only there for green points makes your engine dirty and sluggish

Re: The 3.0 GU Engine

Posted: 24 Jul 2016 17:55
by Michael
I would say that removing the cat and installing a proper 2.5" at least or 3" is the best thing you can do for your engine.
Like Josh says it reduces the EGT and ups the power.
He has a Madman and took it for a dyno befor and after the exhaust, so he knows first hand what an investment that is :thumbup:

Re: The 3.0 GU Engine

Posted: 24 Jul 2016 18:39
by Peter Connan
Any manufacturer's official would have to advise you against any modifications. Anything else would leave that manufacturer open to massive liability lawsuits.

The EGR system referred to above is the Exhaust Gas Recirculation system. The purpose of this is to pass some of the exhaust gas through the engine a second time. This reduces emissions but does blow the dirty stuff right back into your engine.

The catalytic converter captures some more of the dirt by reaction with a fine Platinum matrix. A little thought would make it obvious that this would block up after a time, and restrict airflow more and more.

So manufacturers fit these devices for legal and environmental reasons, that have nothing to do with long-term engine reliability. What never gets mentioned is that manufacturing a new car (or possibly even a major engine rebuild) has a far greater negative environmental effect than the emissions would have had.

Throw them as far away as possible, and as mentioned, fit a Madman engine management system so that you can take personal charge of your engine's health.

Re: The 3.0 GU Engine

Posted: 25 Jul 2016 07:16
by David M
Also because the CAT is so restrictive and blows hot air back it heats the Turbo. Always not a good thing.

Removed the CAT's on the Jimny when new and replaced exhaust with freeflow and branch manifold. It is a completely different vehicle that can actually now be driven on a long trip.

Re: The 3.0 GU Engine

Posted: 25 Jul 2016 09:49
by ricster
100% agree with everything said above.... Exhaust gas temperature is your biggest issue on ANY diesel ( regardless of make) so without a shadow of a doubt ..... Fit either a Madman system, or for that matter you can fit any make of EGT gauge ( Pyrometer ). I don't have a Madman system fitted to mine, but the previous owner fitted a MGL system. It measures 2 x EGT and 2 x CHT ( cylinder head temp ) temperatures. The one I have is actually for airplane motors, but the principle is the same and gives me VERY accurate readings. One can go even cheaper route too, and just fit a VDO Pyrometer gauge, but these don't have alarms going off when you hit temps over 650deg C pre turbo.

Re: The 3.0 GU Engine

Posted: 25 Jul 2016 10:24
by Johann 1984
Hi Josh,

I am disturbed. My engine does not look similar to yours. I attach a photo of mine. It says Nissan Direct Injection Turbo Diesel Intercooler. I suppose it's a generation 3 engine then?

Regards

Johann

Re: The 3.0 GU Engine

Posted: 25 Jul 2016 10:30
by Michael
Johann

You have a older gen 2 or 3 engine there and is not the CRD version. probably a gen 3 as you have a very late model

Re: The 3.0 GU Engine

Posted: 25 Jul 2016 10:52
by ricster
Don't stress though. First step.... EGT gauge !!!, second step EGR removal/blanking and bigger straight through exhaust. Then one can play around with dawes valves etc. to achieve optimal performance, and longevity of that motor. Greg ( Juice ) on the forum has the gen 1 ZD30 in his Patrol, and his is still going VERY strong after many many Km.