When you decide to install a replacement BMW 118d engine, whether it’s a rebuilt BMW 118d engine, reconditioned BMW 118d engine, or a used BMW 118d engine, swapping out certain parts is a must to keep it running smoothly for years. Worn components like the timing belt, water pump, or seals can spell trouble if left unchanged. For instance, a dodgy water pump might cause your engine to overheat, and a failing timing belt could lead to serious damage, costing you a fortune in repairs. By replacing these bits during installation, you’re setting your engine up for success and avoiding headaches down the road.