2018 MERCEDES-BENZ G55 AMG

Typical onset: 100,000-150,000 mi

Symptoms: knocking or ticking from bottom end, sudden loss of oil pressure, metal shavings in oil, seized engine

Fix: The M113K is nearly bulletproof with 5,000-mile oil changes, but neglect leads to rod bearing, main bearing, or piston failure. Requires complete engine rebuild or replacement. 40-60 hours labor for removal, teardown, rebuild, and reinstall. Short block replacement is 35-45 hours.

Estimated cost: $15,000-25,000

Typical onset: 80,000-120,000 mi

Symptoms: transmission fluid leaking at radiator area, pink fluid under vehicle, transmission overheating, harsh shifting or slipping

Fix: The transmission cooler integrated into the radiator or external cooler lines corrode and leak. If coolant mixes with ATF, the transmission is destroyed. Catch it early: replace cooler and lines, flush transmission. If contaminated, full transmission replacement required. Cooler/lines only: 3-5 hours. Transmission R&R adds 12-16 hours.

Estimated cost: $800-1,500 (cooler/lines only) or $6,000-9,000 (transmission replacement)

Typical onset: 60,000-100,000 mi

Symptoms: clunking when shifting from park to drive, excessive vibration at idle, visible sagging of transmission, harsh engagement into gear

Fix: The rubber transmission mounts deteriorate and collapse, especially on the rear mount. Replacement requires lifting transmission slightly with a jack. 2-3 hours labor per mount, typically both front and rear done together.

Estimated cost: $600-1,200

Typical onset: 100,000-140,000 mi

Symptoms: whining or grinding noise from supercharger area, loss of boost pressure, check engine light with underboost codes, rubber dust around supercharger pulley

Fix: The Eaton M113 supercharger develops input shaft bearing wear or the rubber coupler disintegrates. Requires supercharger removal, rebuild with new bearings and coupler, reinstall. 8-12 hours labor. Preventive rebuild recommended at 100k miles.

Estimated cost: $2,000-3,500

Typical onset: 50,000-80,000 mi

Symptoms: hard starting after sitting, loss of power under load, hesitation or stumbling on acceleration, fuel pump whining audible in cabin

Fix: The in-tank fuel pump and external fuel filter are often neglected. Filter should be replaced every 30k miles, pump around 80-100k. Filter replacement: 1 hour. Fuel pump requires tank drop: 4-6 hours labor.

Estimated cost: $200-400 (filter) or $1,200-1,800 (pump)

Typical onset: null

Symptoms: white smoke from exhaust, coolant loss with no external leaks, milky oil on dipstick, overheating, misfires

Fix: Usually caused by cooling system neglect (failed thermostat, water pump, or radiator) leading to overheating. Requires cylinder head removal on one or both banks, resurfacing, new gaskets, and ARP studs recommended. 18-25 hours labor for both banks.

Estimated cost: $4,500-7,000

Typical onset: 70,000-110,000 mi

Symptoms: vehicle sits low after sitting overnight, compressor runs constantly, suspension warning light, uneven ride height

Fix: Airmatic struts develop leaks at seals, and the compressor wears out from overwork. Each strut is 2-3 hours, compressor is 3-4 hours. Many owners convert to coil springs ($2k-3k) to eliminate ongoing issues.

Estimated cost: $1,200-2,000 per strut or $1,500-2,200 (compressor)