2010 MERCEDES-BENZ SL

Typical onset: 60,000-120,000 mi

Symptoms: Metallic rattling from engine at startup that disappears when warm, Check engine light with cam/crank correlation codes (P0016, P0017), Sudden loss of power, severe knocking, then complete engine seizure, Metal shavings in oil, scored cylinder walls on teardown

Fix: Balance shaft gears strip or the sprocket bolt backs out, sending metal through the entire engine. No repair—full engine replacement or rebuild required. 25-35 hours labor for R&R plus machine work. Many shops won't rebuild these due to head bolt issues (see below), so used/reman engine is common route.

Estimated cost: $12,000-18,000

Typical onset: 70,000-110,000 mi

Symptoms: Coolant loss with no external leaks, White smoke from exhaust on cold start, Misfires on multiple cylinders, Overheating or coolant in oil (milky dipstick), Head gasket failure that returns after proper repair

Fix: Aluminum block threads strip, head bolts lose torque, head gaskets fail. Cannot just replace gaskets—requires Timesert or Helicoil thread repair on all bolt holes. Both heads off, machine shop time for inserts, resurface heads, new bolts, gaskets. 30-40 hours total. Often discovered during balance shaft failure teardown.

Estimated cost: $8,000-12,000

Typical onset: 80,000-130,000 mi

Symptoms: Harsh shifts, especially 2-3 or 3-4, Limp mode (stuck in 2nd or 3rd gear), Flare on upshifts (RPM spike between gears), Check engine light with transmission codes (P0715, P0700 series)

Fix: Conductor plate (wiring harness inside trans) cracks or valve body solenoids fail. Requires transmission pan drop, sometimes full valve body replacement. 6-10 hours labor depending on whether valve body needs replacement or just conductor plate. Fluid and filter service included.

Estimated cost: $1,800-3,500

Typical onset: 70,000-120,000 mi

Symptoms: Transmission fluid puddles under car (red fluid), Low transmission fluid warning on dash, Burnt transmission smell if driven low on fluid, Visible fluid seepage at cooler connections on radiator

Fix: Steel lines rust where they connect to radiator-mounted cooler, or quick-disconnect fittings crack. Replace both lines plus any damaged fittings. 3-4 hours labor, requires raising car and removing belly pans. Flush and refill transmission fluid.

Estimated cost: $800-1,400

Typical onset: 90,000-140,000 mi

Symptoms: ABC warning light with 'Car too low' or 'Drive carefully' message, One corner of car sagging, especially overnight, Green hydraulic fluid puddles (distinct from coolant), Hissing or whining from hydraulic pump

Fix: ABC struts develop leaks at seals, or hoses/lines crack. Each strut 4-5 hours, lines 2-3 hours depending on location. System requires specialized scan tool to bleed. Often multiple leaks present by the time symptoms appear. OE parts only—no good aftermarket.

Estimated cost: $2,000-5,000

Typical onset: 80,000+ mi or 10+ years

Symptoms: Top operates slowly or stops mid-cycle, Top warning light, 'Close manually' message, Hydraulic fluid stains in trunk near top mechanism, Top leans to one side when closing

Fix: Hydraulic cylinders (usually rear latch cylinders) develop seal leaks. Each cylinder 2-3 hours to replace, system must be bled. Two rear cylinders most common. Convertible top must be partially disassembled for access.

Estimated cost: $1,200-2,200

Typical onset: 90,000-130,000 mi

Symptoms: Rough idle, hesitation, or stalling, Long cranking before start, especially when hot, Loss of power under acceleration, Check engine light with fuel trim or pressure codes

Fix: In-tank fuel pump or filter assembly fails. Tank must be dropped (4-5 hours labor). This generation has two pumps in the saddle tank. Recommend replacing both pumps and filter assembly as a set since labor is 90% of the job.

Estimated cost: $1,500-2,500