Engine Oil Leak
A BMW Z4 2.0 petrol, year 2011, was brought to the workshop. Engine oil is leaking from the front section of the cover (cylinder head). The cylinder head cover gasket was replaced during the last service, but the oil stain still appears in the same location.
What could be causing this oil leak?
1. The same issue has occurred in other BMW models with engine code N20, manufactured between: 01/03/11-01/10/11. The oil leak is due to an inadequate design of the timing chain tensioner seal washer assembly. Chain noise may be noticeable.
Check and adjust the valve timing if necessary. Then remove the tensioner and inspect the seal washer (see image below).
2. Reinstall the adjusted tensioner and tighten it to the correct torque specification. Afterward, thoroughly clean the entire area and perform a road test to ensure the issue has been resolved.
