2004 MERCEDES-BENZ SLK32 AMG R170

Typical onset: 60,000-100,000 mi

Symptoms: Whining or grinding noise from supercharger at idle or light throttle, Metal shavings in supercharger oil, Catastrophic engine knock from bearing failure, Check engine light with misfire codes after bearing damage

Fix: The supercharger oil pump fails or the feed/return lines clog, starving the blower bearings. Metal debris circulates into the engine, destroying rod and main bearings. Prevention requires supercharger oil changes every 30k and line inspection. Once bearings are damaged, you're looking at a full engine rebuild or short block replacement. 25-35 hours labor for short block swap, plus supercharger rebuild.

Estimated cost: $8,000-15,000

Typical onset: 80,000-120,000 mi

Symptoms: Transmission fluid appears milky or strawberry-colored, Coolant level drops without external leaks, Harsh or delayed shifts, Overheating transmission or engine

Fix: The cooler inside the radiator develops internal leaks, mixing coolant and ATF. This destroys the 5-speed auto (722.6) quickly. Requires radiator replacement, complete transmission fluid flush (or trans rebuild if contamination went unnoticed), and sometimes auxiliary cooler install for prevention. 4-6 hours for radiator and flush; add 18-24 hours if transmission needs rebuild.

Estimated cost: $1,200-2,500 (preventive) / $4,500-7,000 (with trans rebuild)

Typical onset: 70,000-110,000 mi

Symptoms: Top operates slowly or stops mid-cycle, Hydraulic fluid leaking from pump or cylinders, Clicking or grinding from pump motor, Top stuck in partially open position

Fix: The hydraulic pump, cylinders, or hoses fail from age and heat cycling. Pump motor is behind passenger seat. Full diagnosis requires pressure testing. Pump replacement is 3-4 hours; cylinders add another 2-3 hours each. Often multiple components fail together on high-mileage cars.

Estimated cost: $1,500-3,500

Typical onset: 60,000-90,000 mi

Symptoms: Clunk when shifting from Park to Drive/Reverse, Vibration at idle in gear, Visible sagging of transmission when inspected from below

Fix: The rear transmission mount disintegrates from heat and torque. The trans literally drops and impacts the crossmember. Replace with OEM or upgraded urethane mount. 2-3 hours labor, straightforward job.

Estimated cost: $400-700

Symptoms: Random no-start condition, cranks but won't fire, Stalling while driving, typically restarts after sitting, Check engine light with crank sensor code P0335/P0336

Fix: Heat from the supercharger and exhaust cooks the crank sensor on the bellhousing. Fails intermittently at first, then leaves you stranded. Sensor itself is cheap but access requires removing the starter and working in tight quarters. 2 hours labor.

Estimated cost: $350-550

Typical onset: 100,000-150,000 mi

Symptoms: Rattling noise from front of engine on cold start, Metallic debris in oil filter during changes, Noise disappears once engine reaches operating temp

Fix: The balance shaft drive gears wear and create noise. Not immediately catastrophic but generates metal that circulates through the engine. Requires front engine disassembly to replace gears. Some techs delete the balance shafts entirely. 12-16 hours labor.

Estimated cost: $2,500-4,000