Is the BMW S85 engine reliable?
The S85 is prone to several issues, including rod bearing wear, VANOS solenoid failure, and throttle actuator problems. High oil consumption is common, particularly as the engine ages. The advanced design and intricate components make the S85 difficult and expensive to repair and maintain. A well-known problem with the S85 is premature rod bearing wear, which can occur around 80,000 km or roughly 50,000 miles. The root cause is attributed to the engine’s high-revving nature, tight tolerances and a lack of clearance between the rod bearings and the rod journals.The root cause is attributed to the engine’s high-revving nature, tight tolerances and a lack of clearance between the rod bearings and the rod journals.