Get a code reader diagnostic tool that can speak the language of the vehicle- Carly Pro app with their bluetooth connector is a great value in my opinion.

Check your operating temp and verify that you are over 75* C. Thermostat fails open and causes lots of issues.

Understand the technology and the vehicle, it's technical but not rocket science.

Use quality parts and correct fluids. Catch problems early.

Almost identical engine in 335d, it's an M57 ya know.

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03 3.0 Alpine/Blk (sold) Sport, Prem, CWP, PDC, Xenon
10 35d Titanium/Blk - Sport, Lux Seating, Prem, CWP, Tech, Rr Climate, CA