BMW Knowledge Base

Technical articles, diagnostic guides and deep dives into problem BMW components.

951 articles in the base · updated regularly

All Cooling System 22 OBD-II Diagnostics 34 Transmission 16 Buying Guide 60 Engine Mechanical 377 Car Overview 327 Maintenance 47 Suspension 1 Electrical System 24

Engine series:

All B47 B48 B57 B58 N20 N47 N52 N57 S55 S58

Engine Mechanical ⚡ Express

S55 Engine Rattle: The BMW F80 Competition Camshaft Problem and How to Fix It

Learn why the S55 engine rattles on cold start in the BMW F80 Competition, how to diagnose exhaust camshaft deformation, and how to repair it correctly. Includes a checklist for used-car buyers.

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Engine Mechanical ⚡ Express

BMW M4 (F82) with the S55 Engine: Full Guide to Reliability, Tuning, and Buying

A complete guide to the BMW M4 (F82) and its S55 engine: reliability, common problems (crank hub, intercooler, J-pipe, differential bushing), tuning from Stage 1 to 700+ hp, a pre-purchase checklist, and upgrade recommendations.

Engine Mechanical ⚡ Express

S55 Crank Hub: Why It’s the Achilles’ Heel of the BMW M2/M3/M4 and How to Reinforce It

The S55 in the BMW M2/M3/M4 is powerful but vulnerable. Find out why the crankshaft hub is its Achilles' heel, how to reinforce it, what else goes wrong, and what to check before you buy.