2007 MERCEDES-BENZ CLK350 C209

Typical onset: 60,000-120,000 mi

Symptoms: Rattling noise from timing cover area on cold start that disappears when warm, Metallic scraping or grinding from front of engine, Check engine light with timing correlation codes (P0016, P0017, P0018), Sudden loss of power and catastrophic failure if gear teeth strip completely

Fix: The plastic balance shaft gears strip teeth and can take out timing chains, guides, and send debris throughout the engine. Proper fix requires removing timing cover, replacing all balance shaft gears with updated metal versions, new chains, guides, tensioners. If caught early: 12-16 hours labor. If it grenades: complete engine rebuild or replacement at 30-50 hours.

Estimated cost: $3,500-6,000 preventive; $8,000-15,000 if engine damage occurs

Typical onset: 80,000-140,000 mi

Symptoms: Harsh or delayed shifts, especially 2-3 and 3-4, Limp mode activation, stuck in one gear, Erratic shifting patterns or flaring between gears, Transmission fault codes for pressure control solenoids

Fix: The 722.6 five-speed develops internal valve body wear and the conductor plate (13-pin connector) cracks solder joints. Requires dropping pan, replacing valve body assembly and conductor plate, fresh fluid and filter. 6-8 hours labor with proper diagnostics.

Estimated cost: $2,000-3,500

Typical onset: 70,000-130,000 mi

Symptoms: Check engine light with P0010, P0011, P0020, P0021 codes, Rough idle and poor cold-start performance, Reduced power and fuel economy, Intermittent stalling at idle

Fix: The cam adjusters (variable valve timing solenoids) fail or the position sensors go bad. Each bank has separate components. Replacing all four solenoids plus sensors is common preventive approach. 3-5 hours labor depending on how many need replacement.

Estimated cost: $800-1,800

Typical onset: 90,000-150,000 mi

Symptoms: Transmission fluid puddles under vehicle, usually pink/red, Low transmission fluid warnings, Burning smell from fluid dripping on exhaust, Transmission overheating if fluid level drops significantly

Fix: The metal transmission cooler lines corrode where they connect to radiator or at crimp joints. Sometimes just fittings/seals, but often requires replacing entire line assemblies. 2-4 hours labor.

Estimated cost: $600-1,200

Typical onset: 60,000-100,000 mi

Symptoms: Oil consumption increases noticeably, Rough idle and hesitation, Oil leaks from valve cover gaskets or oil cap, Whistling noise from engine bay

Fix: The PCV valve and internal baffles in valve covers clog with sludge, causing pressure buildup. Proper fix involves removing valve covers, cleaning or replacing internal components, new gaskets. 4-6 hours labor if doing both banks.

Estimated cost: $800-1,500

Typical onset: 80,000-120,000 mi

Symptoms: Suspension warning light illuminated, Vehicle sits low on one or both front corners, Compressor runs constantly, Harsh ride quality, bottoming out over bumps

Fix: Air struts develop leaks in rubber bladders. Can replace with OEM air struts (expensive, will fail again) or convert to conventional coil-over setup. Air strut replacement: 2-3 hours per corner. Coilover conversion kit: 4-6 hours for front.

Estimated cost: $1,200-2,000 per strut OEM; $1,500-2,500 coilover conversion