2008 MERCEDES-BENZ S600

Typical onset: 60,000-100,000 mi

Symptoms: Metallic knocking or rattling from lower engine, especially on cold start, Low oil pressure warning intermittently or persistently, Metal shavings/glitter in oil during changes, Sudden catastrophic failure with complete engine seizure

Fix: The M275 has a known weakness where main and rod bearings starve for oil due to inadequate oiling system design and tight tolerances. Once knocking starts, the crank journals are usually scored. Fix requires full engine-out teardown: crankshaft removal, journal inspection/machining or replacement, all bearings, often pistons and rings due to debris contamination. Some shops recommend full short-block replacement to avoid comebacks. Engine-out labor alone is 30-40 hours, plus machine work. Many owners opt for used engine swaps at 25-30 hours labor.

Estimated cost: $15,000-35,000

Typical onset: 80,000-130,000 mi

Symptoms: Blue smoke on acceleration or at idle, Loss of boost pressure and significant power reduction, Loud whining or whistling noise from engine bay, Oil consumption increases noticeably, Check engine light with boost pressure fault codes

Fix: The twin turbos on the M275 fail from worn bearings and seal deterioration. Often one fails first, but best practice is replacing both since labor overlaps significantly and the second typically follows within 20k miles. Requires removal of extensive intake and cooling components. 16-22 hours labor per side, but doing both simultaneously saves ~10 hours total. OEM turbos only—aftermarket has poor track record.

Estimated cost: $8,000-14,000

Typical onset: 70,000-110,000 mi

Symptoms: "ABC malfunction, visit workshop" message on dash, Car sagging on one corner, especially after sitting overnight, Hydraulic fluid leaks visible under vehicle (greenish fluid), Rough ride quality with loss of adaptive damping, Whining noise from hydraulic pump

Fix: The ABC system uses hydraulic struts that leak internally and externally. Struts alone run 6-8 hours per corner. Hydraulic pump failures add another 8-10 hours. Pulsation damper (common failure) is 4-6 hours. ABC valve block can fail requiring 12-15 hours. System requires specialized pressure bleeding procedure. Many owners eventually convert to conventional suspension (coil conversion kits exist) at 20-25 hours labor to escape ongoing ABC costs.

Estimated cost: $3,500-8,000

Typical onset: 90,000-140,000 mi

Symptoms: Harsh or delayed shifts, especially 2-3 and 3-4, Transmission slipping or flaring during upshifts, Gear selector displays dashes instead of gear, Transmission fluid contamination with metal particles, Limp mode with trans locked in gear

Fix: The 722.9 seven-speed has a valve body with solenoids that wear and stick, causing erratic shifting. The external oil cooler is known to fail internally, contaminating fluid. Valve body replacement is 8-12 hours with programming. Oil cooler replacement is 6-8 hours. If cooler fails and contaminates system, full flush and often torque converter replacement required, pushing total to 18-25 hours. Conductor plate (internal wiring harness) also fails occasionally, adding complexity.

Estimated cost: $4,000-9,000

Typical onset: 80,000-120,000 mi

Symptoms: "Airmatic malfunction" warning on startup, Vehicle sits low, especially rear, after sitting, Compressor runs excessively or constantly, Compressor makes grinding or squealing noise, One corner drops overnight indicating strut leak

Fix: Many S600s have Airmatic air suspension instead of or in addition to ABC (some have both systems—ABC up front, Airmatic rear). Compressor typically fails first from overwork due to leaking struts. Compressor replacement is 3-5 hours. Air struts are 2-3 hours each. Valve block occasionally fails adding 4-6 hours. Unlike ABC, aftermarket air struts (Arnott) are viable and cost half of OEM with good reliability.

Estimated cost: $2,000-5,000

Typical onset: null

Symptoms: Extended cranking before engine starts, Rough idle or misfires across multiple cylinders, Fuel smell in cabin or around vehicle, Check engine light with fuel system lean/rich codes, Loss of power under acceleration

Fix: The V12 has two fuel pumps, two fuel filters, and complex fuel distribution. Fuel filters clog prematurely if tank contamination occurs—filters are 2-3 hours labor combined. Fuel pumps fail requiring tank drop at 8-10 hours. Fuel pressure regulators and dampers leak causing fire risk and rough running—6-8 hours labor to access under intake manifolds. Injectors rarely fail but are $300+ each when they do.

Estimated cost: $1,500-4,500