2005 MERCEDES-BENZ C230 KOMPRESSOR W203

Typical onset: 75,000-120,000 mi

Symptoms: Loud rattling on cold start that fades as engine warms, Check engine light with timing correlation codes (P0016, P0017), Metal shavings in oil, catastrophic engine failure if ignored, Rough idle and loss of power

Fix: Balance shaft sprocket uses a pressed bushing that fails, causing timing chain slack and potential valve-piston contact. Requires front timing cover removal, chain replacement, balance shaft module replacement, and often cam adjusters. 12-16 labor hours if caught early; full short block or engine replacement if it grenades (20-30 hours).

Estimated cost: $3,500-6,000 preventive; $8,000-12,000 for engine rebuild/replacement

Typical onset: 80,000-130,000 mi

Symptoms: Whining or squealing noise on acceleration, Loss of boost pressure and performance, Oil leaking from supercharger snout seal, P0236 or P0299 boost pressure codes

Fix: Eaton M45 supercharger develops worn input shaft bearings and rubber coupler deterioration. Requires supercharger removal, bearing replacement, coupler replacement, and often new seals. Some techs rebuild on-car, others send to specialty shops. 6-8 hours labor for coupler; 8-12 hours for full rebuild.

Estimated cost: $1,200-2,000 coupler only; $2,500-4,000 full rebuild

Typical onset: 60,000-100,000 mi

Symptoms: Rough idle, especially when cold, P0011, P0021 cam position timing codes, Rattling noise from valve cover area, Poor fuel economy and sluggish acceleration

Fix: Intake and exhaust cam adjusters seize or solenoids clog from sludge buildup. Requires valve cover removal, timing chain tensioner release, and adjuster replacement. Oil changes every 5k miles critical for prevention. 4-6 hours labor.

Estimated cost: $1,200-2,200

Typical onset: 90,000-140,000 mi

Symptoms: Harsh or delayed shifts, especially 2-3 and 3-4, Limp mode with transmission warning light, P0715, P0720 speed sensor codes, Slipping or flaring on upshifts

Fix: The 722.6 transmission's 13-pin conductor plate (circuit board) cracks solder joints, causing erratic shifting. Requires pan drop, valve body removal, and conductor plate replacement. Also address seals and filter while in there. Often coincides with failing oil cooler seals. 6-8 hours labor.

Estimated cost: $1,800-3,200

Typical onset: 70,000-110,000 mi

Symptoms: Excessive vibration at idle in Drive, Clunking when shifting from Park to Drive or Reverse, Engine rocking visibly on acceleration or deceleration, Driveline shudder

Fix: Hydraulic engine mounts and transmission mounts deteriorate, causing excessive drivetrain movement. Right engine mount most prone to failure. Requires lift, support of powertrain, and mount replacement. 2-4 hours labor depending on which mounts.

Estimated cost: $600-1,200 for pair

Typical onset: 80,000-120,000 mi

Symptoms: P2004, P2006 runner control stuck codes, Slight loss of low-end torque, Check engine light, Rattling from intake manifold

Fix: Variable intake manifold flaps stick or actuator motor fails due to carbon buildup. Can sometimes clean and free up, but often requires manifold removal and actuator replacement. 3-5 hours labor.

Estimated cost: $800-1,400

Typical onset: 50,000-90,000 mi

Symptoms: Excessive oil consumption (1 qt per 1,000 mi or worse), Oil in intake tract and intercooler, Rough idle and hesitation, Smoke from tailpipe on deceleration

Fix: Oil separator (integrated into valve cover) clogs, causing crankcase pressure and oil sucked into intake. Requires valve cover replacement with integrated breather system. On early M271s this is chronic. 3-4 hours labor.

Estimated cost: $700-1,200