2002 MERCEDES-BENZ SLK230 KOMPRESSOR R170

Typical onset: 80,000-140,000 mi

Symptoms: Excessive oil consumption (quart per 500-1000 miles), Blue smoke on startup or acceleration, Rod knock or bottom-end rattle, Loss of compression, misfires, Metallic debris in oil

Fix: The M111 Kompressor suffers from piston ring land failure, scored cylinder walls, and bearing wear due to oil coking from supercharger heat. Most need full rebuilds with upgraded pistons or short block replacement. Expect 25-35 labor hours for engine-out rebuild, or 18-22 hours for short block swap.

Estimated cost: $4,500-8,500

Typical onset: 70,000-120,000 mi

Symptoms: Pink or milky transmission fluid (coolant intrusion), Chocolate milk appearance in coolant reservoir (trans fluid intrusion), Harsh shifting or slipping, Transmission overheating warnings, Coolant loss with no visible leaks

Fix: The internal transmission cooler in the radiator fails, allowing coolant and ATF to mix. Requires radiator replacement, full transmission fluid flush (often multiple times), and frequently transmission rebuild if driven after contamination. Radiator replacement alone is 3-4 hours, but contaminated trans adds 12-18 hours.

Estimated cost: $800-1,200 (caught early) or $3,500-5,500 (with transmission damage)

Typical onset: 90,000-150,000 mi

Symptoms: Overheating, especially under load, White smoke from exhaust, Coolant loss without external leaks, Rough idle, misfires, Oil cap with milky residue

Fix: M111 head gaskets fail from repeated heat cycles and inadequate cooling system maintenance. Requires cylinder head removal, resurfacing, and valve work often needed. 14-18 labor hours. Common to find warped heads requiring machining or replacement.

Estimated cost: $2,800-4,500

Typical onset: 60,000-100,000 mi

Symptoms: Loss of power under boost, Heat soak, poor performance in warm weather, No supercharger whine change but reduced power, Check engine light with charge air temp codes

Fix: The electric water pump that cools the intercooler fails, causing intake air temps to skyrocket and reducing power. Pump itself is accessible but system needs bleeding properly. 2-3 labor hours.

Estimated cost: $600-900

Typical onset: 60,000-90,000 mi

Symptoms: Clunking when shifting from Park to Drive/Reverse, Vibration at idle in gear, Excessive driveline movement visible from below, Harsh engagement into gear

Fix: Fluid-filled transmission mounts deteriorate and collapse, causing harsh shifts and vibration. Replacement is straightforward with transmission support. 1.5-2.5 labor hours.

Estimated cost: $400-700

Typical onset: 80,000-130,000 mi

Symptoms: Top operates slowly or gets stuck mid-cycle, Hydraulic fluid puddles in trunk, Top won't latch properly, Asymmetric operation (one side slower)

Fix: Hydraulic cylinders develop seal leaks over time. Requires cylinder removal and rebuild or replacement. System must be bled afterward. 4-6 labor hours depending on which cylinders fail.

Estimated cost: $800-1,400

Typical onset: 70,000-120,000 mi

Symptoms: Random no-start condition (cranks but won't fire), Stalling while driving, usually restarts after cooling, Intermittent check engine light with crank/cam correlation codes, Loss of tachometer reading

Fix: Heat-related sensor failure is common on M111 engines. Sensor is behind the supercharger, requiring removal for access. 2.5-3.5 labor hours.

Estimated cost: $450-750