BMW M3/M4 (F80/F82) Buyer's Guide: S55 Engine Problems and Reliability (2015-2020)

Introduced in 2014 (2015 model year), the F80 M3 and F82/F83 M4 brought a shift from naturally aspirated V8 to a twin-turbo inline-six. The S55 engine delivers strong performance but introduces several failure points that can lead to thousands in repairs. The most critical risk is crank hub slip, which can destroy the engine on both tuned and stock cars. Understanding these issues before you buy is essential to finding an F80/F82 that's a joy to own rather than an expensive project.

Generation Overview

The F80 M3 (sedan) and F82 M4 (coupe) / F83 M4 (convertible) were produced from 2015 to 2020. All variants use the 3.0L twin-turbo S55 I6, rated at 425 hp (431 hp with Competition Package). Mid-cycle changes in 2018 brought updated iDrive, LED headlights, and minor suspension tweaks. The Competition Package (ZCP) added 19 hp, adaptive dampers, and a revised exhaust. This generation is praised for its chassis balance and daily usability but marred by a common engine vulnerability.

Pricing Guide

Here is what you can expect to pay for an F80/F82 in 2026: 2015-2016 M3/M4: $30,000-$40,000 (40,000-70,000 miles) 2017-2018 M3/M4: $38,000-$50,000 (25,000-50,000 miles) 2019-2020 M3/M4 (Competition): $48,000-$60,000 (15,000-35,000 miles)

Competition Package cars command a $3,000-5,000 premium. Manual transmission models are $2,000-4,000 more than DCT. Convertible (F83) models are $3,000- 5,000 less than coupes due to the added weight and complexity. Low-mileage, well-documented examples at the higher end of the range are almost always worth the premium.

Known Issues

Crank Hub Spin

The S55's crank hub is keyed but the bolt can loosen, allowing the hub to spin relative to the crankshaft. This shifts cam timing, often leading to bent valves or piston/valve contact. Reports are most frequent on tuned cars (higher boost and rev limits) but stock examples have also failed. Severity: Critical. What to watch for: check engine light with timing-related codes (e.g., 130308, 13010A); rough idle or misfire on cold start. Prevention: aftermarket crank hub capture or pinned hub ($1,500-2,500 installed). This is the most important preventative maintenance you can do on an S55-powered car.

S55 Carbon Buildup

Direct injection leaves no fuel wash over intake valves, causing carbon deposits that restrict airflow. Symptoms include reduced power, rough idle, and misfire codes. All S55 engines require walnut blasting every 40,000-60,000 miles, costing $800-$1,200. Severity: Medium. What to watch for: black smoke from exhaust on cold start; gradual power loss above 5,000 RPM. If the car has 40,000+ miles and no documented carbon cleaning, budget for it immediately.

Charge Air Cooler Coolant Leaks

The S55 uses a hybrid air-to-water intercooler system; the charge air cooler bricks are submerged in coolant and can develop internal cracks. Coolant mixes with intake air, causing misfires and potential hydrolock. Reported across all model years, often after 40,000 miles. Severity: High. What to watch for: coolant smell from vents, white smoke from exhaust, frequent coolant loss with no external leak. Repair costs $2,000-3,500 for replacement.

Exhaust Flap Rattle

The M4 and M3's active exhaust has a vacuum-actuated flap that develops a metallic rattle on cold start, especially in Sport or Sport+ modes. This is a cosmetic sound issue, not mechanical failure. Severity: Low. What to watch for: rattle that disappears as engine warms or exhaust valve closes. Some owners disable the exhaust flap or replace the actuator to resolve it.

Crankcase Vent Valve Failure

The PCV system is integrated into the valve cover. The diaphragm can rupture, causing high crankcase pressure, oil leaks, or vacuum issues. Affects all S55 engines, often between 50,000-80,000 miles. Severity: Medium. What to watch for: whistling noise from engine bay, oil seepage around valve cover, rough idle after deceleration. Valve cover replacement costs $800-1,200.