Your Nissan Navara engine keeps your vehicle ticking along, but when it starts to falter, the warning signs can creep up fast. Look out for excessive smoke billowing from the exhaust—whether it’s blue, black, or white—or strange noises like knocking or rattling under the bonnet. You might also notice a drop in power when accelerating or spot oil pooling under the car. These clues often point to worn-out bits like piston rings or gaskets, or even trouble with the cylinder heads. Catching these early can stop a small hiccup from turning into a full-blown breakdown, saving you a hefty repair bill down the road.