2013 MERCEDES-BENZ S63 AMG

Typical onset: 40,000-80,000 mi

Symptoms: Coolant mixing with oil (milky dipstick/cap), White smoke from exhaust, Sudden overheating with no external leaks, Rough idle or misfire codes, Catastrophic failure can occur without warning

Fix: Factory head bolts stretch and fail, causing head gasket breach and coolant intrusion into cylinders. Often destroys pistons, rods, bearings. Most need complete short block replacement (all pistons, rings, bearings, machine work) plus both head gaskets and updated bolts. 40-60 hours labor. This is THE killer issue on M157 engines.

Estimated cost: $18,000-35,000

Typical onset: 60,000-100,000 mi

Symptoms: Transmission fluid leaking near front of engine bay, Pink/red fluid pooling under vehicle, Transmission slipping or harsh shifts if fluid level drops, Burning smell from hot fluid on exhaust

Fix: Cooler lines crack at crimped fittings or corrode through. Replacing lines requires removing front undertray and sometimes radiator support for access. 4-6 hours labor plus fluid refill and adaptation with Star Diagnostic System (SDS).

Estimated cost: $1,200-2,200

Typical onset: 50,000-90,000 mi

Symptoms: Clunk or thud on hard acceleration or deceleration, Vibration at idle in Drive, Driveline shudder during gear changes, Visible sagging or torn rubber on mount inspection

Fix: The MCT transmission weighs substantially more than conventional autos and eats mounts. Front and rear mounts often need replacement together. Requires lifting transmission slightly. 3-4 hours labor for both.

Estimated cost: $800-1,400

Typical onset: 70,000-120,000 mi

Symptoms: Rattling noise from engine bay on cold start (first 30 seconds), Reduced boost/power, Check engine light with underboost codes (P0299, P0234), Turbo flutter or chattering under load

Fix: Wastegate actuator arms wear and rattle, eventually stick. Can replace actuators separately or entire turbo assemblies if shaft play is excessive. Each side 6-8 hours due to tight packaging and exhaust manifold removal. Often do both sides preemptively.

Estimated cost: $3,500-6,500

Typical onset: 80,000-130,000 mi

Symptoms: Vehicle sitting low on one corner after sitting overnight, Airmatic warning message on dash, Compressor running excessively (can hear cycling), Uneven ride height side-to-side

Fix: Air struts develop leaks at bellows or seals. Front struts 2.5-3 hours each, rears 2-3 hours. Compressor often overworked if driven long with leaking strut—inspect/replace as needed. Programming required after strut replacement.

Estimated cost: $1,800-2,800 per strut

Typical onset: 70,000-110,000 mi

Symptoms: ABC warning light and message (car too low), Green hydraulic fluid leaking under vehicle, Suspension sags to bump stops when parked, Rough ride, loss of adaptive damping, Pulsation pump running continuously

Fix: If equipped with ABC (not all S63s have it—some use Airmatic), struts, lines, pulsation damper, and valve blocks leak. ABC repairs are brutally expensive. Strut replacement 4-6 hours each, plus system flush and bleed. Many owners convert to conventional coilovers instead.

Estimated cost: $3,000-6,000 per corner, conversion kits $4,000-7,000