2024 Nissan X-TRAIL Pricing and Specs

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.