2001 MERCEDES-BENZ SLK230 KOMPRESSOR R170

Typical onset: 80,000-140,000 mi

Symptoms: Low oil pressure warning light at idle when hot, Knocking or ticking from lower engine block, Metallic rattling on cold starts that worsens, Metal shavings in oil filter during changes

Fix: The M111 supercharged engine suffers from inadequate oil squirters and bearing design. Full engine rebuild with upgraded bearings, new pistons, rings, and often crankshaft machining required. 18-24 hours labor for removal, rebuild, and reinstallation. Many owners opt for low-mileage used engine swap instead at 12-16 hours labor.

Estimated cost: $4,500-8,000

Typical onset: 70,000-110,000 mi

Symptoms: Pink or milky transmission fluid, Transmission slipping or delayed engagement, Transmission fluid leaking near radiator, Overheating transmission especially in summer traffic

Fix: The transmission cooler lines corrode and leak, and the cooler itself becomes clogged with debris. If ignored, contaminated fluid destroys the 722.6 five-speed transmission. Proper fix requires new cooler, all lines, full fluid flush, and often new transmission valve body or full rebuild if damage occurred. Cooler/lines alone: 3-4 hours. If transmission is damaged: 10-14 hours for rebuild or R&R.

Estimated cost: $800-1,200 (preventive) / $3,500-5,500 (with transmission damage)

Typical onset: 90,000-130,000 mi

Symptoms: Whining or grinding noise from front of engine that increases with RPM, Oil leaking from supercharger nose, Loss of boost pressure, Check engine light with boost control codes

Fix: The Eaton M45 supercharger develops bearing wear in the nose cone, causing oil leaks and noise. Requires supercharger removal, disassembly, new bearings, seals, and coupler. Some shops send units out for rebuild. 6-8 hours labor plus rebuild cost or reman unit.

Estimated cost: $1,200-2,000

Typical onset: 60,000-100,000 mi

Symptoms: Clunking when shifting from Park to Drive or Reverse, Excessive vibration at idle in gear, Visible transmission sag when inspected from below, Harsh engagement when accelerating from stop

Fix: The rear transmission mount deteriorates and allows excessive drivetrain movement. Requires lift access and support of transmission. Aftermarket mounts fail quickly; use OE Mercedes part. 1.5-2 hours labor.

Estimated cost: $300-500

Symptoms: Roof stops mid-cycle and won't complete operation, Hydraulic fluid leaking in trunk area, Clicking relay sound but no roof movement, Roof microswitches out of alignment preventing operation

Fix: The Vario roof system has multiple failure points: hydraulic pump/motor, cylinders, lines, microswitches, and control module. Diagnosis takes 1-2 hours. Pump replacement 3-4 hours, cylinders 4-6 hours. Microswitch adjustment sometimes solves issues for free. Many owners live with manual latching if repairs exceed car value.

Estimated cost: $500-2,500 depending on component

Typical onset: 70,000-120,000 mi

Symptoms: Rough idle and hesitation, Check engine light with P0100-P0104 codes, Poor fuel economy, Cracked or collapsed rubber intake boot between MAF and throttle body

Fix: The MAF sensor fails causing poor running, and the rubber accordion boot cracks allowing unmetered air. Replace both together. MAF requires genuine Bosch unit or quality reman; cheap aftermarket sensors cause more problems. 0.5-1 hour labor.

Estimated cost: $400-650