2002 MERCEDES-BENZ G500 W463

Typical onset: 80,000-150,000 mi

Symptoms: excessive oil consumption (1+ qt per 500 mi), white/blue smoke on startup or acceleration, sudden loss of compression in one or more cylinders, coolant in oil or oil in coolant, metallic knocking or rattling from engine

Fix: Engine rebuild with oversize pistons and re-sleeved cylinders (20-30 hrs), or short block replacement (18-25 hrs). Some owners opt for used long block swap (12-16 hrs) but risk inheriting same problem. M113 engines from this era had weak Nikasil cylinder linings that score and crack, especially with low-quality fuel or extended oil change intervals. Once it starts, it cascades fast.

Estimated cost: $8,000-15,000

Typical onset: 70,000-120,000 mi

Symptoms: transmission fluid in coolant or vice versa (milkshake in reservoir), erratic shifting or transmission slipping, overheating transmission, pink/red fluid visible in coolant expansion tank

Fix: Replace transmission oil cooler and flush both cooling system and transmission (4-6 hrs). Critical to catch early before contamination destroys transmission internals. If fluid mixing has occurred for any length of time, transmission rebuild may be necessary (add 12-18 hrs).

Estimated cost: $800-1,500 for cooler only; $3,500-5,500 if trans is damaged

Typical onset: 60,000-100,000 mi

Symptoms: heavy clunk when shifting from park to drive/reverse, excessive vibration at idle in gear, driveline shudder on acceleration, visible sagging or torn rubber on mount inspection

Fix: Replace transmission mount and often engine mounts at same time since labor overlaps (3-5 hrs for trans mount alone, 6-8 hrs if doing all mounts). G-Wagen mounts take more abuse than typical SUV due to off-road capability and vehicle weight.

Estimated cost: $600-1,200 for trans mount; $1,500-2,500 for all mounts

Typical onset: 80,000-140,000 mi

Symptoms: oil dripping from center of undercarriage, oil spots under vehicle after parking, low transfer case fluid level on inspection, whining or grinding from transfer case under load

Fix: Replace front or rear output shaft seals (2-4 hrs depending on which seal). If caught late, internal damage from low fluid requires transfer case rebuild or replacement (12-16 hrs). These seals harden with age and miles.

Estimated cost: $400-800 for seal replacement; $2,500-4,000 for rebuild

Typical onset: 90,000-150,000 mi

Symptoms: whining or groaning when turning wheel, heavy steering effort, especially when cold, power steering fluid leaks under vehicle or on pump, foamy or dark power steering fluid

Fix: Replace power steering pump (2-3 hrs) or high-pressure hoses (1.5-2.5 hrs). The G-Wagen's hydraulic steering system works hard with oversized tires and off-road use. Pumps wear out, and the hoses crack from heat cycling. Flush system when replacing components.

Estimated cost: $600-1,200

Symptoms: hard starting after sitting, engine stumbling or hesitation under acceleration, loss of power at highway speeds, engine stalling when fuel tank below 1/4

Fix: Replace fuel filter (0.5-1 hr) first as maintenance item every 30k miles. If pump is failing, replace in-tank fuel pump assembly (2-3 hrs). G500s are sensitive to old fuel and sediment; these often sit for extended periods or see infrequent use, leading to varnish buildup.

Estimated cost: $100-200 for filter; $800-1,400 for pump

Typical onset: 70,000-120,000 mi

Symptoms: clicking or popping when turning at low speed, vibration during acceleration, torn CV boot with grease visible on wheel/suspension, clunking from front axle over bumps

Fix: Replace CV axle assembly (2-3 hrs per side). The solid front axle with locking differential puts stress on CV joints, especially with larger tires or off-road use. Boots tear, water/dirt intrude, joint fails. Don't ignore torn boots or you'll be replacing the whole axle.

Estimated cost: $500-900 per side