Nissan Navara Engine Problems

There are literally dozens of things that can make a check-engine light illuminate, Kathleen. A faulty sensor, dud component, bad or dirty fuel, a vacuum leak, you name it, even the smallest glitch can cause the dreaded check-engine light to ruin your day.

The best advice is to take the car back to the workshop that serviced it and ask if, perhaps, the mechanic forgot to tighten or reset something properly. An interrogation by the workshop’s computer should throw up any fault codes present and from there, the workshop should be able to figure out the actual problem. It could be a coincidence, but, equally, it could be a simple thing the workshop has overlooked or forgotten to reset during the service.

No. While the D40 Navara did have warning lights for things like contaminated diesel fuel and a warning light for the Diesel Particulate Filter (DPF) the Navara didn’t stretch to a light to warn that maintenance to the camshaft timing system was due. That’s mainly because the Navara’s four-cylinder turbo-diesel engine used a timing chain rather than a rubber timing belt, and the chain should have been good for the life of the engine.

Experience has shown, however, that the YD25 engines that used a single-row primary timing chain did, indeed, experience premature chain wear and failure in some cases. And this is probably at the root of your question. The trade now recommends that these chains be changed before the 80,000km mark, with inspections every 40,000km to make sure nothing is wearing out too fast. The aftermarket has developed a double-row replacement timing chain for these engines, so any replacement of the chain should take this into account.

There’s no rule about when cars should or shouldn’t need repair. That Nissan has offered you a deal to cover half the cost of a replacement turbocharger is tantamount to an admission that the turbocharger shouldn’t have failed at that distance. If you feel that Nissan’s offer isn’t up to scratch take them to VCAT.

The chances are it will get worse, and leaving it is likely to make the repair more expensive when you finally have to do it. Find out what is causing it and fix it.

You need to get the air out of the system by pressing the priming valve, which is a big button on top of the fuel filter housing. You’ll have to do it up to 50 times or so, slowly, once every two seconds. If it doesn’t start then, prime it again.

The car’s electronic brain has observed some issue with the engine. Take it to a dealer or a mechanic with diagnostic gear and they should be able to isolate the cause and fix the problem.

This sounds like a classic case of a hydraulic lifter (also called a lash adjuster) that is dying a slow death. These components rely on engine oil pressure to maintain the correct clearance between the engine valves and the rockers that actuate them, and any wear will show up as a ticking noise when the engine is first started and is still building oil pressure. They can often 'tick' for a few seconds or more before going quiet.

The recurrence of the noise has probably got something to do with a fall in oil pressure at idle when the engine warms up, allowing the lifter to start ticking again. But the engines in this series of Navara were also known for ticking or rattling noises as the result of worn camshaft-chain tensioners, broken or damaged cam bearing bolts and wear in the auxiliary pulleys and belt tensioners. If the noise does turn out to be a dud lifter, do the smart thing and replace them all, as wear in one means certain wear beginning in the others.

This model Navara was known for a couple of faults that could cause it to enter limp-home mode (which sounds like what’s happened given the engine is no longer making full power). The first was a batch of dud exhaust-gas temperature sensors which had a habit of dying young. If that happened, the engine would go into limp-home mode to avoid overheating (and damaging) the turbocharger, even though there was no actual problem beyond the sensor itself.

The other problem with the 2.5-litre turbo-diesel was that the primary timing chain was a single-row item that was, frankly, underdone and could stretch before the vehicle had covered even 80,000km. If that happened, the camshaft-position sensor would become confused and could trigger a limp-home condition. There’s a replacement timing chain that is actually double-row (stronger) that many owners fit as a solution.

As with any other problems like this one, Terry, the best advice is to have the car plugged in to a scanner and have a diagnostic mechanic read the fault codes which will hopefully give an idea of the cause of the limp-home mode and unresponsive throttle pedal. It could be something simple, it may be something really intrinsic, but without a scan, you’re flying blind.

The oil in the intercooler, meanwhile, is a potentially big problem. A little oil inside the intercooler piping is actually quite normal and is usually the result of oil mist from the crankcase ventilation system condensing and leaving a little oily residue. But a large amount of oil in the intercooler suggests a turbocharger with leaking seals and/or bearings. If the seals are leaking, boost pressure from the turbocharger can force oil from the turbo’s bearing into the intercooler. If that’s the case, you’re looking at a rebuilt or new turbocharger unit. A blown turbo could also be enough to prompt the limp-home mode you’re experiencing.

Get it to a diesel mechanic, but if you can’t check the fuel pump.