BMW engines to avoid in used cars: top 5 unreliable models

© © A. Krivonosov

Like any other manufacturer, BMW isn't perfect, and its engines haven't always been the picture of reliability. Here's a list of five engines from the German brand that you might want to avoid when buying a used car.

N47 Diesel

This engine is notorious for frequent failures of its timing chain. The chain is located in an extremely awkward and hard-to-reach spot, making replacement very expensive for owners. Moreover, a timing chain failure often leads to serious engine damage, such as bent pistons and valves, which drives up repair costs even further.

N63 V8

The N63 engine features an eight-cylinder V-configuration. Early versions of this powerplant had numerous issues, including cylinder block overheating, excessive oil consumption, and characteristic knocking noises. Engineers later revised the design, eliminating most of these problems, but early models continue to cause significant headaches for BMW owners.

S85 V10

The heart of the legendary third-generation M5 and M6 models delivers outstanding power and performance, giving the car impressive acceleration and high top speeds. However, maintaining such an engine is costly even when it's running smoothly. A key weak point is the connecting rod bearings, which are prone to rapid wear and require replacement at specific mileage intervals.

N54

On its own, this engine is quite reliable and can last a long time with proper maintenance. Nevertheless, owners often face issues with auxiliary components. The most common problems involve failures of the high-pressure fuel pump, fuel injectors, and worn valve cover gaskets. All these parts need regular replacement to prevent engine misfires or even complete stalling.

N73 V12

As one of BMW's flagship engines, with twelve cylinders and a massive displacement, the N73 became a true symbol of the brand's luxury and exclusivity. But its complex design meant that any engine trouble translated into major financial outlays. Frequent service visits were due to failures in the fuel pump and cooling system, with repair costs significantly higher than average for other BMW models.