Nissan Patrol Engine Problems

You said it yourself; it's tired, so I wouldn't fit a turbocharger without rebuilding the engine. You'd be asking for trouble to do it without doing the engine.

While the ZD30 engine should have been a major step forward in terms of technology with common-rail technology and double overhead camshafts, in reality, the engine was not one of Nissan’s finest moments. Bottom end failures were not uncommon with cracked pistons necessitating full rebuilds.

Several causes have been suggested including poor fuel-air ratio management and boost spikes form the turbocharger putting sudden, huge loads on the engine’s internals. Either way, though, the engine is far from remembered fondly.

CarsGuide has looked at this engine in depth, and even published a guide to the Nissan Patrol ZD30 engine.

From what you say it would appear the engine output is below what it should be, and the high fuel consumption would seem to reflect that. The output should be 118 kW at 3200 rpm and 380 Nm at 2000 rpm. Persist with the dealer, and Nissan, the company has a responsibility to fix your car. Your idea of having a Nissan rep ride with you as you demonstrate the problem is a good one.

I assume you mean it’s higher than normal, because these were thirsty trucks to begin with. The 4.8-litre petrol six-cylinder engine could easily consume 20 litres per 100km at freeway speeds and a lot more around town or in the bush. Even the turbo-diesels were no sippers.

But a sudden jump in fuel consumption can often be traced back to either tuning or a glitch in part of the fuelling system. Make sure the car is serviced and has a clean air filter and new spark plugs (if it’s a petrol engine). You can also have the fuel-injection system checked to make sure you don’t have a stuck injector that is pouring fuel into the engine when it doesn’t need it.

If the engine is fit and healthy, you can then make sure the car doesn’t have a dragging brake or another mechanical problem that is – literally – dragging it down. Don’t ignore the other basics, either; under-inflated tyres can also cause high fuel consumption. And, have you fitted a roof rack lately? These can easily add a full litre per 100km to your overall consumption figures, just through wind-drag.

You need to talk directly to the dealer and explain that you believe they have sold you a car with defective engine mounts and ask that they replace them for you. Even though the warranty has expired they might be willing to fix the problem on the basis of goodwill, but you will only know that if you talk to them.

The ZD30 will probably not be remembered as one of Nissan’s greatest engines. In good condition and running properly, they’re not a bad unit, but they have managed to develop a reputation for – as you’ve identified – giving problems long before they should.

Any off-roader’s engine is liable to overheat, especially when you’re working it hard in the bush with minimal air-flow through the radiator. Many Patrol owners have identified this and fitted larger, aftermarket radiators to fix the issue. A bigger worry is the engine’s propensity to explode – usually – number three of four piston with catastrophic results.

The trade has a few theories including a build-up of oil and soot (which forms black gunk) that partially blocks the inlet tract that causes uneven mixtures across all four cylinders. At that point, you could have hot-spots occurring that can potentially melt pistons. Another theory holds that the same black gunk was messing with the engine’s sensors and allowing them to send false information back to the computer, again leading to incorrect air-fuel mixtures.

Boost spikes were another problem, apparently caused by the engine’s slow response to commands from the computer. In extreme cases, turbo-boost could increase violently and damage pistons. Even then, it wasn’t that simple, because Nissan itself seems to have misunderstood the engine, originally specifying an oil capacity of too little, leading to oil starvation and engine damage. The company quickly added a couple of litres to the specification (for a total of 8.3 litres) and instructed its dealers to shorten and recalibrate dipsticks when the cars came in for servicing.

For all that, the ZD30 has gathered its admirers who value its performance and reduced fuel consumption over some other turbo-diesel Patrol engines. For our money though, if you can afford it, the bigger, less stressed TD42 turbo-diesel is the pick of the Patrol engines from this era. The catch there is that the TD42 was only available with a five-speed manual while the ZD30 could be had with an optional four-speed automatic.

 The top hose temperature, if what you say is correct, is way too low, it should be up around 100 degrees, hence the low bottom hose temperature. I would suspect the thermostat is stuck open.

I don’t believe that what you want is out there, and can only reiterate past advice, buy a Patrol/Pajero/Prado/LandCruiser.

Worn glow-plugs will certainly make a diesel engine difficult to start and can easily contribute lots of smoke to the equation. But in reality, you could be looking at anything from worn or dribbling injectors, a blocked air-intake system, a worn fuel pump or simply internal wear in the engine itself. A worn turbocharger bearing or seal can also cause these problems, and don't forget about the simple stuff like a blocked fuel filter.

Trying to diagnose turbo-diesel engine problems from the colour of the smoke emitted is a hiding to nowhere and you'll inevitably find yourself changing perfectly good parts on a hunch and wasting lots of time and money. The best bet is to take the car to a diesel specialist and have the whole system investigated.

The 4.8-litre six-cylinder petrol engine was last used in the GU 7 in 2012.