Nissan Navara Pricing and Specs

This is actually a pretty common problem and there seems to be two common causes. The first is leaking seals inside the turbocharger. The turbo needs oil to lubricate it, but if its seals are leaking they can allow oil into the inlet tract and, therefore, the intercooler.

The second cause is possibly even more common and involves the crankcase ventilation system allowing oil into the intake (and intercooler). A modern engine needs to consume its own crankcase fumes and burn them (rather than vent them into the atmosphere) as part of its anti-pollution systems. But in many cars (and modern turbo-diesels are the prime suspects) those fumes can contain some oil mist which, once enough of it has accumulated, will form the oil droplets you’re seeing in the intercooler.

While a faulty turbocharger will need to be replaced, if the problem is the work of the crankcase ventilation system, it still should be addressed before the oil mixes with soot from the exhaust gas recirculation system (another emissions-control device) and forms a horrible, back gunk that clogs the engine’s intake system. If hat happens, costly disassembly and cleaning is required.

Even if you’ve caught this in the early stages (before the gunk can build up) the oil can still cause problems with sensors inside the inlet system and could cause poor running and high fuel consumption. A good quality oil catch can is the preferred method of stopping this occurring as it 'catches' the oil mist before it gets to the inlet tract.

It sounds very much like your car has a problem with what’s called its clockspring. This is an electrical contact that allows the functions controlled by, or mounted on, the steering wheel to operate while still allowing the wheel to be turned. Over time, the clockspring wears and finally breaks which is almost certainly why you lost the cruise control and horn functions at the same time. It’s also why the airbag light has illuminated, as the broken connector won’t allow the computer to talk to the airbag in the steering wheel.

Most workshops will be able to replace the clockspring, but unless you’re a competent mechanic, leave it to the experts as anything to do with an airbag requires utmost care and respect. Even the experts will disconnect the car’s battery before tackling any airbag issue.

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.