It's typical BMW arrogance. It would be amusing if BMW did not make it a habit of screwing up M3 production engines. They have created a tradition of engine defects. The past three generations of M3 models all suffer from some sort of engine issue from the factory.
The E46 M3's S54 motor initially developed a poor reputation due to a large string of engine failures. This was attributed to the rod bearings. We're talking well over 100 engine failures right off the bat.
This was simply piss poor quality control from BMW. In other words, they made a mistake. BMW's explanation was that rod bearings were manufactured to the wrong clearance and were too tight resulting in inadequate oil film between the rod bearing and crank journal.
Maybe that was the case. Maybe BMW realized their original spec did not work over the long term and so they issued a recall with larger clearances. They also decided to change the rod bolts so there seems to be more to it than just a manufacturing error. Getting BMW to admit they made a mistake of this magnitude is almost impossible though.
The problem was solved in the recall at least temporarily. People still experience high bearing wear but redesigning the entire crank was not as cost effective of a solution as new bolts and bearing clearances.
BMW pretended the issue did not exist until every BMW forum was talking about it and an engine failure registry kept collecting entries. They finally issued the recall.
BMW screwed up on the S54 but they definitely learned their lesson with the E92 M3 and the new 4.0 liter S65 V8, right? After all, this was BMW's new race motor and they needed it to be reliable.
Not exactly. The S65 also experiences bearing wear issues. If BMW did not get cute and cheap with the oil system and instead offered higher oil pressure and consistent lubrication from say a dry sump oil system that would definitely alleviate some of the wear problems. BMW simply got cheap and the oiling system was not the 'quasi dry-sump' system from the S85 V10 which the engine is based on but a pretty basic wet sump system.
It is not just the oiling system to blame although that is the main culprit. There was a class action suit brought against BMW which alleged the following regarding the S65 engine:
The plaintiffs claim when the connecting rod bearings and main bearings start to fail, metal debris from the bearings is circulated in the oil throughout the engine. According to the BMW M3 owners, the rotating assembly is a safety risk due to the failure of the bearings that can cause total engine failure. The plaintiffs say the engine can fail while driving and at any speed due to the bearings not having enough lubrication.
Owners change bearings as preventative maintenance but if you are out of the warranty period it almost feels like a ticking time bomb. BMW does not care and just wants cars out of the warranty period as quickly as possible so they can wash their hands of any issue. If you intend to track your M3 a dry sump system is a must.
Their race car engines receive much higher quality oiling systems, bearings, rods, etc., based on the S65 design so issues are alleviated. Owners of the street car are not so fortunate.
Which brings us the F80 M3 generation. Surely, BMW did not screw up for a third straight generation? Oh yes, they did, as we covered in detail in our previous article on the S55 crank hub spinning problem.
Unlike the S54 and S65 motors that see bearing and oiling issues the S55 experiences a crank hub failure. BMW simply plugged in the N54/N55 geometry with updates but they did not design a bespoke M3 engine. It's BMW cost cutting rearing its head again. However, it's also a very different issue with no documented solution thus far. It may be the worst BMW M3 engine mistake they ever made.
We will not rehash the previous article on the topic but it is important to note BMW refuses to even acknowledge the issue. Motors are being replaced by dealers and there is plenty of evidence of this on any BMW forum.
BimmerBoost asked BMW almost a month ago about this issue and sent the e-mail to multiple BMW sources. Every single one of them has refused to comment thus far. It's the S54 cover up all over again.
BimmerBoost members are currently testing various options including a new bolt design which hopefully rectifies the issue but there is no denying BMW factory M3 engine defects are now a tradition.
BMW has its flaws and its marketed image versus the reality (and reliability) of its products are vastly different things. They will chase profit over proper design.