BMW Timing Chain Problems: An Engine-by-Engine Overview
The timing chain is the most expensive weak point on many BMW engines. The N47 and N57 diesels are especially problematic, with the N20 gasoline engine close behind. A stretched or broken chain leads to a full engine rebuild. Below is a systematic breakdown by engine: symptoms, fault codes, diagnosis, prevention, and the repair sequence.
Which Engines Are Affected
| Engine | Type | Production Years | Risk |
|---|---|---|---|
| N47 / N57 | Diesel | 2007–2014 | High |
| N20 | Gasoline | 2011–2017 | High |
| N52 | Gasoline | — | Low |
| N54 | Gasoline | — | Low |
| B48 | Gasoline | — | Notably better than N20 |
| B58 | Gasoline | — | Considered very reliable |
Two families are affected above all: the N47/N57 diesels built 2007–2014 and the N20 gasoline engines built 2011–2017. The N52, N54, and B58 are largely immune to chain stretch. The B48 is a much better design than the N20—thanks to an improved chain and tensioner.
Symptoms
- A loud rattle on cold start, lasting 5–15 seconds.
- A knock at idle that fades as revs climb.
- Power loss and limp mode.
- Metal shavings in the oil filter.
- In the worst case, the engine won’t start—the chain has jumped.
A chain letting go without warning is rare. The rattle and fault codes usually give you weeks of notice. Ignoring the symptoms ends in an engine rebuild.
Fault Codes
| Code | Meaning |
|---|---|
| P0016 | Crankshaft/camshaft correlation, bank 1, intake |
| P0017 | Crankshaft/camshaft correlation, bank 1, exhaust |
| P0018 | Crankshaft/camshaft correlation, bank 2, intake |
| P0019 | Crankshaft/camshaft correlation, bank 2, exhaust |
| 2A82 | VANOS target position—often points to chain stretch |
| 2A99 | Camshaft reference mark implausible |
Codes P0016–P0019 describe a mismatch between the crankshaft and the camshafts. 2A82 is a VANOS target position fault; it often appears precisely because the chain has stretched, while 2A99 flags an implausible camshaft reference mark.
Diagnosis
The main method is ISTA live data. If camshaft deviation exceeds 8 degrees at the crankshaft, that points to chain stretch. Supporting signs are codes P0016/P0017 and the telltale rattle for 5–15 seconds after a cold start. Metal shavings in the oil filter confirm the wear.
Repair
On the N47 you have to pull the engine or drop the transmission—hence the highest labor bill. The N20 takes less work. On the B48/B58 the chain is harder to replace than on the N20, but it needs replacing less often.
Timing chain repair is one of the most expensive engine jobs. The N47 is the priciest of all: the chain kit plus labor pushes the total toward the cost of an engine rebuild. The N20 comes in cheaper. An authorized BMW shop charges a 30 to 60 percent premium over independent shop prices, so the final dealer bill is noticeably higher.
Prevention
- Only 5W-30 or 0W-30 LL-04 oil.
- Oil change interval—9,000 miles at most. That matters more than the oil brand.
- Short change intervals.