Quote:
Originally Posted by RockDriver
What I am concerned about is the likelihood of catastrophic failure costing 5 figures to repair.
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Potentially costly repairs on F15:
timing chains,
CP4 fuel pump,
front driveshaft
Noteworthy but not a major concern:
transmission,
emissions system
Timing chains
Anecdotally in USA many enthusiasts feel that extended oil change intervals (OCI) of ten thousand miles, and short urban drive cycles, can hasten timing chain wear. It is a labor-intensive engine-out repair because the timing chains are located at the rear of the engine.
General consensus among enthusiasts wanting to keep their N57 healthy for long-term ownership is:
A) perform oil changes more frequently, e.g. every 6,000 miles; and,
B) disable the "automatic stop/start" feature to keep the engine running uninterrupted
CP4 fuel pump
If it fails, shrapnel contaminates the lines, tank, injectors. Everything must be replaced. Failure rate is much lower on the revised/updated pump with set screws.
Front driveshaft
E70 and now F15 can experience front driveshaft failure. If it fails, it can damage nearby components: transfer case, transmission, oil pan. This can be very costly. It is recommended to inspect the front driveshaft for evidence of corrosion and/or wobble in the splines. An American member of this forum, named Tony, sells a replacement driveshaft with longer splines to address one of the factors that lead to premature failure.
"Front driveshaft?" post #31
These next two are noteworthy but unlikely to require costly repair:
Transmission service
Service the transmission over 100k miles. The transmission manufacturer recommends it. Ignore BMW stance -- BMW says lifetime fill because they stopped doing free filter replacements.
Emissions system
Short answer: The system is quite durable. There are many OBD2 smartphone apps to monitor the engine's health, diagnose error codes, etc. DPF is costly if it gets clogged and needs to be cleaned or replaced, but this rarely happens.
Longer answer: In USA many enthusiasts proactively remove fully-functioning emissions systems because they believe it is failure-prone. Honestly, the real reason they remove it is because they prefer the performance gains that come from a turbo-back straight-pipe exhaust running higher boost levels. The downside is smell and smoke from tailpipes (some are more smokey than others). If you desire increased performance, there are upgrade "tunes" that provide a modest increase in power while keep the emissions system intact thereby avoiding smell and smoke.