2002 MERCEDES-BENZ C32 AMG

Typical onset: 80,000-130,000 mi

Symptoms: Rod knock on cold start or under load—often starts subtle and escalates fast, Metal shavings in oil during routine changes, Loss of power, misfires, or sudden catastrophic failure (grenaded block)

Fix: The M112 supercharged suffers from harmonics that fatigue rod bearings prematurely, especially if oil changes were delayed or wrong oil used. Common fix is short block replacement or full engine rebuild with upgraded bearings and pistons. Engine-out job: 18-25 hours labor depending on ancillary damage. Many owners opt for used longblock swaps to save cost.

Estimated cost: $8,000-15,000

Typical onset: 70,000-120,000 mi

Symptoms: Transmission slipping, especially 2-3 shift or under hard acceleration, Burnt ATF smell, dark red or brown fluid, External leaks at cooler lines (steel lines crack at crimps), Limp mode or no upshifts after spirited driving

Fix: The factory cooler and lines are undersized for AMG power and heat. Lines crack, ATF overheats, and clutch packs burn. Replace cooler lines (2 hrs), add auxiliary cooler (3 hrs), and flush/refill. If slipping already started, expect valve body or full rebuild—transmission out is 8-12 hours. Preventive cooler upgrade is critical.

Estimated cost: $800-1,200 (lines/cooler) or $3,500-5,500 (rebuild)

Typical onset: 90,000-140,000 mi

Symptoms: Whining or grinding noise from front of engine, especially at idle or light throttle, Loss of boost pressure—car feels flat above 4,000 rpm, Visible coupler damage or oil leaking from snout seal

Fix: Eaton M62 supercharger snout bearing wears and the rubber coupler between crank and blower cracks. Supercharger must come off (4-6 hours) for bearing/seal kit and coupler replacement. If caught early, no internal damage; delayed fixes risk snout seizure and blower destruction.

Estimated cost: $1,200-2,000

Typical onset: 100,000-150,000 mi

Symptoms: Coolant loss with no visible external leaks, White smoke from exhaust on startup, Oil in coolant or coolant in oil (milky dipstick), Overheating or rough idle with misfire codes

Fix: M112 supercharged runs higher cylinder pressures than NA versions; head gaskets eventually weep coolant into cylinders or oil passages. Heads-off job on both banks: 12-16 hours. Often discover warped heads requiring machining or replacement. Use OE gaskets and ARP studs if rebuilding.

Estimated cost: $3,500-6,000

Typical onset: 60,000-110,000 mi

Symptoms: No-start or stalling—especially when engine is hot, Intermittent rough idle and hesitation, Check engine light with crank/cam correlation codes (P0335, P0340)

Fix: Heat from supercharger and exhaust cooks these sensors prematurely. Crank sensor is behind the starter (2 hours with starter removal); cam sensors are on valve covers (1 hour each). Cheap parts, moderate labor. Keep spares in the glovebox for track/road trip insurance.

Estimated cost: $300-600

Typical onset: 70,000-120,000 mi

Symptoms: Severe clunking on 1-2 shift or throttle tip-in, Excessive engine movement visible under hood during acceleration, Vibration through chassis at idle in Drive

Fix: AMG torque shreds the hydraulic mounts. Transmission mount (easiest, 1.5 hours) usually fails first; engine mounts follow. Replace all three simultaneously to avoid repeated visits. Aftermarket solid mounts reduce service life but eliminate slop—trade comfort for response.

Estimated cost: $800-1,400

Typical onset: 80,000-130,000 mi

Symptoms: Stumble or hesitation under full throttle above 5,000 rpm, Long crank before starting when hot, Lean codes or fuel trims maxed out

Fix: In-tank pump struggles to supply supercharged V6 at high flow demands; filter (under car near tank) clogs if fuel quality is poor. Filter change is 1 hour; pump replacement requires tank drop (4-5 hours). Replace filter every 30k as preventive—cheap insurance.

Estimated cost: $200-350 (filter) or $900-1,400 (pump)