The coupe and convertible variant of the 3 Series platform — shared engines, shared failure patterns, and a sharper roofline. F32 models are in their prime used-market years. G22 examples are just beginning to appear at accessible price points in the Ventura County market.
The 4 Series shares its chassis, engines, and most mechanical components with the F30/G20 3 Series. That means the 4 Series maintenance profile and failure patterns mirror the 3 Series almost exactly. If you've read the 3 Series guide, you've read most of what you need to know mechanically. The body style and equipment choices are the real differentiators.
Read the 3 Series guide →The N20 four-cylinder in F32 428i models carries the same documented timing chain tensioner concern as the F30 328i. A cold-start rattle that dissipates within seconds is an early indicator. Any used F32 428i purchase should confirm whether this has been addressed — BMW extended warranty coverage, but many examples are past that window.
The F32 435i with the N55 inline-six is generally considered the stronger used buy over the 428i. The N55 avoids the N20 timing chain concern, produces significantly more power, and has a well-understood maintenance profile. Oil leaks at the valve cover and oil filter housing are expected on higher-mileage examples — budget for them at purchase and negotiate accordingly.
The 440i introduced mid-cycle uses an updated N55 or early B58 depending on production date. B58-equipped 440i examples are among the most capable and reliable modern BMW coupes available in the current used market. The B58's improved cooling and lower internal stress make it a meaningfully different ownership proposition than the N55.
All F32 engines use direct injection. Intake valve carbon buildup follows the same 60,000–80,000 mile timeline as the 3 Series equivalents. Short-trip driving patterns — common in Simi Valley's suburban layout — accelerate buildup. Walnut blasting is the remedy.
F33 428i and 435i convertibles have specific soft top maintenance requirements. The drainage channels that route water away from the folded top area can clog with debris — particularly in areas like Simi Valley where oak leaves, eucalyptus, and other organic debris accumulate. Clogged drains lead to water intrusion. Cleaning the drains annually prevents a relatively minor maintenance task from becoming a significant interior repair.
The G22 4 Series with B46/B48 four-cylinder or B58 inline-six represents BMW's current coupe architecture. The G22 M440i xDrive with the B58 is particularly well-regarded — one of the more complete sporting coupes BMW has produced. G22 examples are beginning to surface in the Ventura County used market as leases return and three-year-old examples hit the lot.
G22 failure patterns are still emerging. The B48 and B58 engines are proving to be robust with proper maintenance. Transfer case fluid service on xDrive models, cooling system monitoring, and software currency via ISTA are the primary preventive priorities for G22 owners.
N20 timing chain diagnosis, N55 and B58 oil leak repair, walnut blasting, carbon cleaning, and pre-purchase inspections for F32, F33, F36, and G22 models. German Auto Doctor handles the full 4 Series range for owners in the 805.
Service by German Auto Doctor · 521 E Los Angeles Ave, Simi Valley CA 93065