Nissan Patrol Problems

You could be looking at something internally wrong with the transmission, but the clue that this might be something simpler is in the way the engine will start in Reverse which, of course, it shouldn’t (for safety reasons). The suspicion would be that the relationship between the selector (inside the cabin) and the actual gearbox is somehow out of synch. So when the selector is telling you the car is in Reverse, it’s actually in Park or Neutral, which is why the engine will start.

That might also explain why the car won’t select fourth gear; the position that actually coincides with Drive (or fourth gear) looks – from inside the cabin – to be the Neutral position. So, to check this, put the car in what looks like Neutral and, in a safe place, see if it moves when you give it some throttle.

Failing that, you’ve got two separate problems. The first is the inability to select fourth gear (which could be a hundred things) and a failure of the safety switch which is allowing the engine to start in Reverse.

You could be dealing with either a worn transmission itself (where wear inside the gearsets, shafts or torque converter has made something sloppy) or there’s something else in the driveline (such as a differential or universal joint) that has likewise allowed some looseness or play to enter the equation. In either of those cases, a thump or clunk during shifts can be a symptom. It feels worse under acceleration, as that’s when the maximum stress is on all those moving, meshing parts.

Sometimes, a transmission can be serviced and adjusted to get rid of thumping or banging during shifts. Take the car to a transmission specialist who will be familiar with this transmission and may be able to return it to civility.

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.

If you still want to drive a proper off-road four-wheel-drive, then maybe fixing what you already have is the wise way to go. Supply crunches and high demand have seen the prices of second-hand four-wheel-drives skyrocket. You might be in for a shock when you check the prices of second-hand replacements.

Beyond that, it comes down to the overall condition of the rest of the vehicle. Off-roaders are big, heavy and sometimes complex machines and if the rest of the mechanical package isn’t in good condition, fitting a new engine will only attend to one of the vehicle’s ongoing cost-centres.

Four-wheel-drives like the Patrol tend to do big mileages, so you often see them advertised with overhauled or reconditioned engines. That’s not a problem provided the work has been done properly and quality parts used.

But you also need to talk to the seller and determine exactly what they mean by `overhauled’. A true overhaul will have included reconditioning the cylinder head, boring the cylinders, new pistons, new bearings, rings and even things like a new water pump and fuel pump. The receipts form the rebuild will tell the full story.

Our bet would be on the car you’re looking at having had a piston failure (number three or four piston) which was too common on the ZD30 engine. At which point you need to find out whether the engine was completely rebuilt, or simply had a new set of pistons and a new turbocharger fitted.

You really have two ways to go here. The fact that you want to go off-road in the best/worst conditions this country has to offer means an SUV or cross-over just isn’t going to cut it. With that in mind, you’re looking at either a dual-cab ute or a conventional four-wheel-drive wagon.

In the ute world, there’s plenty of choice within your budget, but you need to be careful that the vehicle in question hasn’t been worked to death by a tradie towing a bobcat Monday to Friday. The popularity of these vehicles, meanwhile, means that there’s lots of choice when it comes to aftermarket bits and pieces to complete your dream vehicle.

The other route – a conventional wagon-style 4X4 – also places a lot of choice within your budget. The Toyota LandCruiser Prado would be a good choice, as would something like a Mitsubishi Pajero which has always represented good value for money both brand-new and second-hand. You could also look at Nissan Patrols which also give you plenty of car for the money and, if you shop carefully, you could find a really nice LandCruiser 80 Series, reckoned by some to be the absolute pinnacle of off-road wagons, even though they’re getting on a bit now. There’s great aftermarket and service support for all these options, so it will come down to your personal preferences.

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.

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.