2014 BMW 525Li Engine-Bay Smoke: Valve-Cover Leak and Broken Timing Guide
A 2014 BMW 525Li with an N20 engine produced a burnt-oil odor and white smoke without abnormal mechanical noise. A hardened valve-cover gasket was leaking onto the exhaust area; opening the engine also exposed a broken timing-chain guide. The workshop renewed the sealing, timing-guide, and oil-contaminated accessory-drive parts, then completed a 30-km dynamic test with stable timing feedback and dry external surfaces.
