Engine bearings support the weight of the crankshaft, allowing it to spin freely inside the engine bay. If the support has gone and you hear a knocking sound in the engine, you can enter your registration details to find a replacement here.
The rotation of the crankshaft is crucially important to the operation of your vehicle. It is exactly what makes your car move, and the engine bearings provide the support for that to happen. They come in a set comprising of rod bearings and main bearings to keep your crankshaft in motion.
Given that they are one of the essential components of a car, they are subject to much wear and tear and often need replacing, but there is a difference in the seriousness of faulty engine bearings.
If your main bearings go then the crankshaft will likely need replacing, but if your rod bearings go the engine itself might need to be rebuilt altogether. It is advised that you consult a specialist mechanic to ensure that you have the correct diagnosis for your car.