BMW Timing Chain Replacement Cost: N47, N57, N20, and B48 Engines

The BMW N47 2.0-liter diesel engine, found in the 1 Series (116d, 118d, 120d) and 3 Series (316d, 318d, 320d) from 2007 to 2014, has the timing chain mounted at the rear of the engine, between the engine block and the transmission bellhousing.

This design means that accessing the chain requires either removing the engine from the car or separating the engine from the transmission while it is still in the vehicle. Either approach adds 4 to 8 hours of labor on top of the chain replacement itself. At BMW specialist rates of $130 to $200 per hour, this additional access time costs $500 to $1,600 in labor alone.

The N47 chain is known to fail between 60,000 and 100,000 miles. The primary failure mode is chain stretch leading to a cold-start rattle that progressively worsens. BMW faced a class action lawsuit in several European countries over the N47 timing chain issue. In some markets, BMW offered extended warranty coverage, though this was not universal.

Symptoms specific to N47: A distinctive 2 to 5 second rattle on cold start, particularly noticeable in cold weather. The rattle comes from the back of the engine (not the front like most chain rattle). P0016 and P0017 codes may appear. In advanced cases, the engine may stall or refuse to start.

The N57 3.0-liter diesel shares the rear-mounted chain design with the N47. Found in the 325d, 330d, 530d, and X5 30d. The larger engine means more weight and tighter packaging, which can make the job even more time-consuming. Expect $3,500 to $5,500 total.

The N57 tends to fail later than the N47, typically between 80,000 and 120,000 miles, but the repair cost is higher due to the larger engine and more expensive parts. Some X5 models with the N57 require engine removal through the bottom of the car, which is a specialist-level job.

The N20 2.0-liter turbo gasoline engine (2012 to 2015, found in 228i, 320i, 328i, 428i, 528i, X1, X3) has a conventional front-mounted timing chain. The common failure is the plastic timing chain guide, which can crack and break. When the guide breaks, the chain can slip or jump teeth.

The B48 (2016+) replaced the N20 and addressed some of the chain guide durability concerns. Chain failures on the B48 are less common but still occur, particularly on earlier production units. Cost is lower ($1,800 to $3,000) because the front-mount design allows conventional access.

Both engines are more affordable to service than the N47/N57 because no engine removal is needed. An independent BMW specialist can typically complete the job in 8 to 12 hours.