Nissan X-TRAIL Problems

Actually, this is simply how a CVT operates. When you load the engine (and towing a caravan is a great way to do that) the transmission will switch to a lower ratio in order to keep the engine in its comfort zone and making enough power to keep everything moving at the speed at which you’ve set the cruise control. Because there are no set ratios in a CVT, this can sound a feel very alien when it happens. It's one of the things many people dislike about CVTs.

When you turn off the cruise control and allow the throttle to return to idle, the car detects that the crisis is over and changes the ratio to allow the engine to slow down as less power is needed. And that’s why it all feels like it’s returning to normal. But, really, what you’re hearing and feeling is just the CVT doing its thing.

This sounds more like a control problem that one with the actual compressor. The body computer is often at fault in cases like this. Part of the body computer’s job is to control things like central locking, power windows and the climate control gear. The fact that the system is cycling between fresh air and recycled air makes us suspect the computer as the culprit. Has this been checked?

Hopefully, you first raised this issue with Nissan all those years ago when the vehicle was still under warranty. If so, then you have what is called a pre-existing condition and even though the car is now out of warranty, Nissan is still obliged to fix it as if the warranty still applied.

There's often a disparity between what a car is insured for and what it might be worth on the second-hand market. In any case, with a worn out engine, its market value would be next to nothing anyway. And with 290,000km on its odometer, you might have trouble finding a buyer willing to take a punt.

That said, even if you put a low-kilometre second-hand engine in it, the fact remains that everything else from the transmission to the wheel bearings, brakes and suspension have also done 290,000km and can be pretty much guaranteed to be fairly worn themselves. You could then find yourself shelling out more money every year to keep the car running on the basis that you'd already spent $10,0000 on a replacement engine. Sometimes it's better to cut your losses and buy something newer.

This model X-Trail is fitted with active lane-keeping assistance which is sort of a helping hand when the driver isn’t keeping the car in the centre of its lane. It could be that this system is what’s causing the car to feel like it wants to pull you into the next lane.

You need to have this checked under warranty as soon as possible, since it’s an obvious safety issue. This isn’t just a Nissan thing, either. Many brands have had complaints about these systems, and in some cases, cars fitted with collision-avoidance systems have been known to slam on the brakes when the car’s camera 'sees' something like a wheelie-bin on the footpath and mistakes it for a truck entering the road. Speaking of which, your lane-keeping assistance is controlled by a camera at the front of the car. Have a quick check to make sure there’s not a huge dead bug confusing the camera.

This model X-Trail used a conventional automatic transmission with a torque converter. There are lots of things that can cause this condition, including a failure of the torque converter or any number of moving parts within the transmission itself.

But the first check is to see if there's sufficient transmission fluid inside the gearbox. Use the transmission dipstick to check the fluid level according to the owner's manual's instructions. A transmission with low fluid can certainly exhibit the symptoms you've noted. A quick fluid top up might put the wheels back in motion.

Bear in mind, however, that the transmission is a sealed unit and should only require top ups if there's a leak somewhere. That leak needs to be identified and fixed or the problem will recur.

You can tell a lot about exhaust smoke by its colour. If it's a blue-grey colour, the smoke is probably from burnt oil. If it's black, excess fuel is probably the cause. Make sure, too, that what you're seeing is not just water vapour that is a normal part of the combustion process and will disappear as the exhaust system heats up and turns that vapour into steam (which is invisible).

But if it really is blue smoke you're seeing, it could be a case of worn out piston rings, or worn valve guides or seals. If it's black smoke, you could have a problem with injectors, the fuel pump, intake system, spark plugs, any number of sensors that control the engine's fuel:air mixture, or about a thousand other things. That fact that the smoke disappears after a while suggests that the engine is happier when it has some heat in it, but really, it shouldn't blow any smoke of any colour at all.

It sounds like you've tackled the obvious causes of this type of vibration. The dual-mass clutch is a prime candidate and any car with worn engine mounts can vibrate when it's running.

Digging deeper will involve ruling things out in a process of elimination. So, to start that process, does the vibration go away when the vehicle is stationary or only when it's moving? If it's the latter, you could have some kind of transmission or tail-shaft problem. Ot perhaps even a warped brake rotor or seized brake caliper.

But if the vibration is there whenever the engine is running, then you need to start to look at things like the harmonic balancer on the front of the crankshaft and whether the engine itself is actually running smoothly (regardless of where the idle is set). The stepper-motor (which controls the idle) could be faulty leading to the engine flaring between gear changes, and an engine that has a blocked exhaust, dirty air-filter or even worn spark plugs can run roughly. It could even be something like camshaft timing that has jumped a tooth, leading the engine to run poorly and contribute the bad vibrations you're feeling. Also, check the rubber drive belt that powers the alternator and power-steering pump. A worn belt or worn out tensioners and pulleys can also create problems like this. Check the power steering pump itself for signs of its seizing or jamming as it turns.

All Nissan models officially sold in Australia with a build-date later than 2004 can use ethanol blended fuel with up to 10 per cent ethanol content. That can reduce fuel costs, because E10 fuel is usually cheaper at the pump. Bear in mind, however, that you might use a little more E10 than non-blended fuel because of the slightly lower energy content of E10.

Beyond that, your X-Trail requires regular petrol with an octane rating of 91, which is pretty much the normal brew on any service-station forecourt. You can use higher octane fuels without harming the car, but there would be little to no benefit in doing so. And your wallet will thank you for not bothering.

You've certainly gone to some extremes to check this out, but your investigations should give you a good clue that the problem is with front axle. So, it could either be the differential that is clattering and making the car judder or, perhaps more likely, the front CV joints which allow the car to drive its front axle while also steering the vehicle. Once you take the load off the front driveshafts (by disconnecting them) the noise stops because the worn CV joints aren't taking the strain of trying to move the car, so they don't make the horrible noise.

In some cases, you can simply replace the worn out CV joints, but there's also the option of complete driveshafts (with new CV joints already fitted) that are a simpler fix if a bit more costly. You can also buy driveshafts new or reconditioned. Its sounds like you're more than skilled enough to tackle this at home.

The X-Trail of that era has an unbraked towing limit of 750kg and a braked limit of 2000kg. On that basis, the short answer is yes, you need to have brakes on your caravan.

But the detail is a little more involved. While you do need a braked trailer (caravan in your case) for the Nissan to handle 960kg safely, those brakes don't necessarily need to be the electric variety. A simpler mechanical braking system would also be acceptable and should work fine on a relatively light van such as the one you've described.

Mechanical brakes are preferred by some users who like the fact that the trailer in question can be used on any car with the required towing limit. In the case of electric brakes, a control unit has to be fitted to the tow-vehicle. That gets a bit complicated and is an extra cost. Larger caravan (over 2000kg GTM) need electric brakes, but mechanical brakes are fine for smaller, lighter vans.