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

BMW M50 Engine: The Complete Guide to Ownership, Problems, and Tuning

The complete guide to the BMW M50 engine: specs, common problems, maintenance schedule, a pre-purchase checklist, and tuning advice. Find out how to make the legendary inline-six last.

Read the article

Engine Mechanical ⚡ Express

The Complete Guide to BMW B57, B48, and B58 Problems: What Every Owner Needs to Know

A complete guide to BMW B57, B48, and B58 engine problems: common failures, maintenance tips, and a used-car buying checklist. Find out how to avoid expensive repairs.

Engine Mechanical ⚡ Express

N46B18 Engine: Features, Lifespan, and Problems of the BMW 316i E46 Motor

The N46B18 is a rare gasoline engine from the BMW 316i E46 (2004–2005): specs, typical problems (overheating, timing chain wear, Valvetronic), maintenance and tuning advice. With proper care, it's good for up to 155,000 miles.

Engine Mechanical Overview

BMW B58 vs S58

The B58 and S58 are both modern turbocharged inline-sixes from BMW's modular engine family — the B58 as the series-performance engine (M340i, M440i, X3/X4 M40i, Z4 M40i, Toyota Supra MK5), the S58 as the M-sport unit with two mono-scroll turbos (M3 G80, M4 G82, X3M, X4M). The architecture shares its bore

Engine Mechanical ⚡ Express

BMW N57 Engine: Service Life, Common Problems, and Tuning—The Complete Owner’s Guide

A complete guide to the BMW N57 engine: technical specifications, common problems (intake manifold coking, timing chain stretch, crankshaft damper wear), maintenance for 186,000+ miles of service life, a pre-purchase checklist, and tuning potential.

Engine Mechanical ⚡ Express

BMW M62TUB44 Timing Chain: Why It Stretches, Symptoms, and Full Replacement

Why the BMW M62TUB44 timing chain stretches past 124,000 miles, how to recognize the cold-start rattle, and what to replace during the repair. A complete checklist for E38, E39, and E53 owners.

Engine Mechanical ⚡ Express

Oil Burning on the BMW N52B25: Causes, Diagnosis, and E90 Engine Repair

Learn the causes of oil burning on the BMW N52B25 (E90): worn valve stem seals, diagnosis, decarbonizing, and a full engine rebuild. Real-world experience plus a used-car buying checklist.

Engine Mechanical Overview

BMW N47 vs B47: Comparing Two Diesels

The N47 (2.0d, 2007–2014) earned the nickname “the timing chain diesel” — no other BMW engine did as much damage to the brand's image. The B47, its successor from 2014, was BMW's targeted rework of exactly those weak points: a far more robust timing chain, revised injectors, improved EGR, and a new block.

Engine Mechanical ⚡ Express

BMW E90 N46B20 PCV Valve: Causes of Failure and Replacement

Learn why the PCV valve fails on the BMW E90 N46B20, the symptoms to watch for, and how to diagnose and replace it. Plus advice on part selection and prevention.

Engine Mechanical ⚡ Express

BMW B48 Engine: Reliability, Maintenance, and Tuning

The BMW B48 is one of the most reliable modern BMW engines. Here's what to know about its design, common problems, maintenance, and tuning—plus owner advice and a buying checklist.