2007 MERCEDES-BENZ SL55 AMG

Typical onset: 60,000-90,000 mi

Symptoms: Coolant loss with no visible external leaks, Supercharger whine changes pitch or becomes louder, Sudden catastrophic engine failure with knocking, loss of oil pressure, Metal shavings in oil, low oil level despite no external leaks

Fix: The intercooler pump fails and leaks coolant into the supercharger, which then gets ingested into the engine through the intake. This causes hydrolock or severe bearing/piston damage. Prevention requires replacing the pump proactively (~3 hours labor). Once damage occurs, you're looking at short block replacement or full rebuild with new pistons, rings, bearings, and sometimes crank work. Engine out, 40-60 hours labor depending on damage extent.

Estimated cost: $15,000-25,000

Typical onset: 70,000-120,000 mi

Symptoms: Transmission fluid leaking from front of vehicle, Harsh shifting or delayed engagement when hot, Transmission slipping under load, Burnt transmission fluid smell

Fix: The 722.6 five-speed transmission cooler lines crack or corrode where they connect to the radiator, causing fluid loss and overheating. If caught early, replacing lines and fluid is 2-3 hours labor. If the trans overheats from low fluid, you're rebuilding or replacing the transmission (20-25 hours labor). The cooler itself can also fail internally, mixing coolant with trans fluid.

Estimated cost: $800-1,200 for lines; $5,000-8,000 for transmission rebuild

Typical onset: 50,000-80,000 mi

Symptoms: Severe clunking when shifting from Park to Drive or Reverse, Vibration at idle that changes with load, Visible sagging of engine or transmission when inspecting from below, Driveline shudder during acceleration

Fix: The hydraulic engine and transmission mounts fail regularly on these high-torque AMG cars. All three mounts (two engine, one transmission) should be replaced together. The right engine mount is particularly problematic. 4-5 hours labor for all three mounts. This is preventive maintenance territory around 60k miles.

Estimated cost: $1,200-1,800

Typical onset: 80,000-120,000 mi

Symptoms: ABC warning light on dash with car sagging to one corner, Hydraulic fluid leaks at struts or lines, Rough ride quality, car bouncing excessively, ABC inactive message, car riding very low

Fix: The ABC system uses hydraulic pressure instead of conventional suspension. Pulsation dampers fail ($400 each, 2 hours labor per corner), struts leak ($1,500-2,000 per corner, 3-4 hours each), and the pump can fail ($2,500 part, 6 hours labor). Many owners convert to conventional coilovers ($3,000-4,000) when multiple components fail, but you lose the active suspension features.

Estimated cost: $1,000-3,000 per corner for OE repair; $8,000-12,000 for pump replacement

Typical onset: 90,000-130,000 mi

Symptoms: Rear of car sagging overnight or after sitting, Compressor running excessively or constantly, Airmatic visit workshop message, Uneven ride height side-to-side

Fix: If equipped with Airmatic instead of ABC (check your build), the air struts leak at the rubber bellows and the compressor wears out from overwork. Rear struts fail first. Each strut is 2-3 hours labor, compressor is 4-5 hours. Aftermarket struts from Arnott are half the price of OE and hold up well.

Estimated cost: $800-1,200 per strut; $1,500-2,000 for compressor

Typical onset: Not mileage-driven, age-related

Symptoms: SBC warning light with message to visit workshop immediately, Brake pedal feels different, reduced power assist, ABS/ESP lights illuminated, Complete loss of power braking in worst cases

Fix: The electrohydraulic brake system pump fails due to age and accumulated brake applications (system counts cycles). Mercedes extended warranty coverage in some regions, but many 2007 models are now out of coverage window. Replacement requires bleeding the entire SBC system with factory scan tool. 6-8 hours labor, pump is $2,500-3,500.

Estimated cost: $3,500-5,000

Typical onset: 100,000-150,000 mi

Symptoms: Long crank time before starting, especially when hot, Stumbling or hesitation under hard acceleration, Fuel smell from rear of vehicle, Check engine light with fuel pressure codes

Fix: The high-pressure fuel pump and fuel filter housing can fail. Filter is integral to the pump assembly on this generation. In-tank pump replacement requires dropping the tank, 4-5 hours labor. Fuel pressure regulator in the engine bay can also leak. This is regular maintenance territory but often neglected.

Estimated cost: $800-1,400