2002 MERCEDES-BENZ ML

Typical onset: 80,000-140,000 mi

Symptoms: Coolant mysteriously disappearing without external leaks, White smoke from exhaust on cold start, Overheating with no obvious cause, Sudden catastrophic failure with coolant entering cylinders, Milky oil on dipstick when internal damage occurs

Fix: M113 blocks from this era are prone to porosity allowing coolant seepage into cylinders. Often progresses to spun bearings, scored cylinder walls, and complete engine destruction. Requires complete engine rebuild or replacement. Labor: 25-35 hours for short block swap, 40+ for full rebuild.

Estimated cost: $6,000-12,000

Typical onset: 70,000-120,000 mi

Symptoms: Transmission fluid leaking at radiator connections, Coolant mixing with ATF creating strawberry milkshake in reservoir, Harsh shifting or complete transmission failure after contamination, Pink or brown coolant in overflow tank

Fix: The cooler lines corrode internally or external fittings crack, allowing cross-contamination that destroys the 722.6 transmission. Requires new cooler lines, radiator flush, often full transmission rebuild if contamination occurred. Prevention means replacing lines proactively. Labor: 3-4 hours for lines only, 18-24 hours if transmission rebuild needed.

Estimated cost: $800-1,200 (lines only), $4,500-7,000 (with transmission rebuild)

Typical onset: 60,000-100,000 mi

Symptoms: Loud clunk when shifting from Park to Drive or Reverse, Excessive driveline vibration at idle in gear, Visible transmission sag when inspected from below, Harsh engagement into gear

Fix: The rubber transmission mount deteriorates and the hydraulic damping fails, allowing excessive drivetrain movement. Common wear item on these. Labor: 2-3 hours with proper support equipment.

Estimated cost: $400-700

Typical onset: 90,000-150,000 mi

Symptoms: External coolant seepage at back of engine, Overheating without obvious leak, Rough idle or misfire on one bank, Coolant smell from HVAC vents

Fix: The V6 is more reliable than the V8 but still suffers head gasket failures, particularly rear cylinder head. Requires both heads off for proper repair. Labor: 14-18 hours for both sides.

Estimated cost: $3,500-5,500

Typical onset: 80,000-130,000 mi

Symptoms: Strong fuel smell in cabin or near vehicle, Visible fuel weeping from filter housing, Hard starting or rough running when filter clogs, Fuel stains on driveway

Fix: The plastic fuel filter housing becomes brittle and cracks, creating fire hazard. Filter itself also clogs if neglected. Should be replaced as preventive maintenance. Labor: 1.5-2 hours.

Estimated cost: $300-500

Typical onset: 70,000-110,000 mi

Symptoms: Front end sagging overnight or after sitting, Compressor running constantly, Suspension warning light illuminated, Uneven ride height side-to-side

Fix: Airmatic struts develop leaks at the rubber bellows. Compressor often damaged from overwork. Many owners convert to conventional coil springs to eliminate ongoing issues. Labor: 4-6 hours for both struts, 3-4 hours for compressor.

Estimated cost: $2,000-3,500 (air struts + compressor), $1,200-1,800 (coil conversion)

Typical onset: 80,000-130,000 mi

Symptoms: Clunking over bumps from front suspension, Wandering steering or poor alignment retention, Visible play when prying on wheel assembly, Complete separation causes wheel to fold under (catastrophic)

Fix: Front lower ball joints wear and can separate without warning, causing loss of vehicle control. Mercedes issued service campaigns for this. Requires control arm replacement as joint is not serviceable separately. Labor: 3-4 hours both sides.

Estimated cost: $800-1,400