The 2015 S600 with the M279 6.0L twin-turbo V12 is a flagship luxury sedan plagued by catastrophic engine failures stemming from poorly-designed hot-V turbos that cook the cylinder heads and valve stems. When these engines let go, they let go hard—expect five-figure repair bills that often exceed the car's used value.
Catastrophic Engine Failure - Valve Stem Seal / Piston Ring Failure
Common · high severity
Typical onset: 40,000-80,000 mi
Symptoms: Excessive blue smoke on startup that persists, Oil consumption 1+ quart per 500-1000 miles, Check engine light with misfire codes (P0300 range), Loss of power and rough idle, Catastrophic bearing failure if run low on oil
Fix: The hot-V turbo design cooks valve stem seals prematurely, leading to oil burning. Once seals fail, oil consumption accelerates and contaminates cylinders, scoring bores and failing rings. Proper fix requires full engine rebuild or short block replacement: 60-80 hours labor including removal, machining, new pistons, rings, bearings, head work, turbo reseal, and reinstall. Many shops won't touch these—expect specialized Mercedes independent or dealer-only work.
Estimated cost: $35,000-55,000
Connecting Rod and Main Bearing Failure
Occasional · high severity
Typical onset: 50,000-90,000 mi
Symptoms: Knocking or ticking noise from lower engine that worsens with RPM, Metallic debris in oil during changes, Sudden catastrophic engine seizure, Oil pressure warning light, Check engine light with low oil pressure codes
Fix: When owners ignore early oil consumption issues or extend service intervals, bearing surfaces get starved and fail. Rod knock means the crank needs measuring, bearings replaced, and often crank grinding or replacement. If a rod lets go, you're looking at complete short block replacement—same 60-80 hour ordeal as above. This is a total-loss scenario for most owners.
Estimated cost: $38,000-60,000
Transmission Oil Cooler Failure
Common · high severity
Typical onset: 60,000-100,000 mi
Symptoms: Transmission fluid in coolant (milky/pink coolant reservoir), Coolant in transmission (burnt smell, slipping, harsh shifts), Transmission overheating warnings, Engine overheating in severe cases, Erratic shifting or limp mode
Fix: The 7-speed MCT transmission cooler is integrated into the radiator assembly and fails internally, cross-contaminating fluids. Requires new radiator, complete transmission fluid flush (often multiple cycles), filter, and pan. If contamination is severe, transmission internals get damaged requiring rebuild or replacement. Caught early: 8-12 hours. With transmission damage: add 25-35 hours. DO NOT drive once fluids mix.
Estimated cost: $2,500-4,500 early / $15,000-25,000 with trans damage
Transmission Mount Failure
Common · medium severity
Typical onset: 50,000-80,000 mi
Symptoms: Clunking when shifting from Park to Drive or Reverse, Vibration through chassis at idle in gear, Harsh engagement into gear, Driveline shudder during acceleration
Fix: The MCT transmission is heavy and the mounts fatigue from the V12's mass and torque. Rubber deteriorates and hydraulic mounts leak. Requires lifting the transmission slightly to access—2.5-4 hours for both motor and transmission mounts together. Use OEM or Corteco—aftermarket junk fails in 10k miles.
Estimated cost: $800-1,500
Fuel System Contamination / Filter Clogging
Occasional · medium severity
Symptoms: Rough idle and stumbling acceleration, Long crank time before starting, Limp mode or reduced power warnings, Fuel pressure fault codes (P0087, P0088), Stalling when hot
Fix: The V12 uses high-pressure direct injection with tight tolerances. Contaminated fuel or degraded in-tank pump screens starve the system. Fuel filter is integrated into the pump module requiring tank drop—5-7 hours. If injectors are clogged, add removal, cleaning or replacement of all 12, plus calibration: additional 8-12 hours. Premium fuel and annual fuel system cleaner treatments help prevent this.
Estimated cost: $1,200-2,000 filter / $4,500-7,500 with injectors
Turbocharger Oil Feed Line and Seal Leaks
Occasional · medium severity
Typical onset: 70,000-110,000 mi
Symptoms: Oil smell in cabin or visible smoke from engine bay, Oil pooling on top of engine or dripping underneath, Blue smoke under boost, Reduced boost pressure or limp mode, Oil consumption without external leaks visible from below
Fix: Hot-V configuration roasts the turbo oil feed and return lines, causing hardening and leaks. Lines run between cylinder banks and are a nightmare to access. Requires partial engine disassembly, intake removal—12-18 hours. If turbo seals have failed from oil starvation, add turbo replacement: 20-28 hours total. This job sucks and most shops will sublet to a specialist.
Estimated cost: $3,500-6,000 lines only / $8,000-14,000 with turbos
Owner tips
Change oil every 5,000 miles MAX with MB 229.5 spec—ignore the 10k interval, it kills these engines
Check oil level every fill-up once past 40k miles; consumption is your early warning system
Use premium fuel exclusively and run fuel system cleaner every oil change
Inspect coolant for any discoloration monthly—catch trans cooler failure before it grenades the transmission
Budget $3,000-5,000 annually for maintenance BEFORE anything breaks—these are $180k cars depreciated to $40k, not cheap to own
Find a Mercedes specialist who has V12 experience BEFORE you need one—dealer rates are $250-350/hr
Absolutely not—unless you're paying cash, have a $20k emergency fund earmarked for engine replacement, and accept it's a financial black hole. Buy the V8 S550 instead.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.
Fitment notes: AGM battery required for start-stop system; located in trunk right side; auxiliary battery also present in engine bay
As an Amazon Associate, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.
Every control module on the 2014-2017 Mercedes-Benz S600 — where it lives, replacement time, and what it takes to program a replacement. Modules marked dealer / factory tool won't work after a part swap alone — budget for programming.
Aftermarket tool coverage varies by software version and vehicle build — treat "aftermarket tool" rows as "usually possible" and verify against your tool maker's coverage list before promising a customer. Spot a wrong location or hour? Tell us — corrections ship fast here.
Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2014-2020 C-Class, CLA, GLA, S-Class, GLC, and GLE vehicles. Please refer to MBUSA's recall report for specific vehicle details. The front roof panel located between the windshield and the panoramic sunroof may not have been bonded correctly to the vehicle during a prior repair, allowing the front panel to detach from the vehicle.
Consequence: A detached roof panel can become a road hazard, increasing the risk of a crash.
Remedy: Dealers will replace the front panel, free of charge. Owner notification letters were mailed on August 2, 2024. Owner notification letters will be mailed in phases, on, March 22,2024, and August 2, 2024. Owners may contact MBUSA customer service at 1-800-367-6372. This recall is an expansion of NHTSA recall number 21V-197.
STRUCTURE:BODY:ROOF AND PILLARS · 21V197000
2021-03-19 · PE21001
Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2017-2020 C300 Coupe, C43 Coupe AMG, C43 AMG, 2015-2020 C300, GLA250, 2016-2018 C350e, CLA45 Coupe AMG, 2015 C400, S65 AMG, 2015-2019 C63 AMG, 2016 C450, 2015-2016 GLA45 AMG, S600, 2016-2020 GLC300, 2017-2019 GLC43 AMG, GLE43 Coupe AMG, 2014-2019 CLA250 Coupe, 2014-2015 CLA45 AMG, 2018 GLC63 AMG, 2014-2017 S550, 2018-2020 S450, 2016-2019 GLE63 Coupe AMG, 2016 GLE450 Coupe, 2014-2020 S63 AMG, 2018-2019 S560, and 2019 GLC350e vehicles equipped with a panoramic sunroof. The front roof panel located between the windshield and the panoramic sunroof may not have been bonded correctly to the vehicle during a prior repair.
Consequence: The adhesive bonding of the front panel might deteriorate, possibly causing the front panel to detach from the vehicle and become a road hazard, increasing the risk of a crash.
Remedy: Mercedes-Benz dealer will remove the bonded panel and will install a new front panel by following the detailed repair instructions and using the approved primer, cleaner and adhesive, free of charge. Owner notification letters were mailed on September 3, 2021 and October 26, 2021. Owners may contact MBUSA customer service at 1-800-367-6372.
COMMUNICATION · 19V787000
2019-11-01
Mercedes-Benz USA, LLC. (MBUSA) is recalling certain 2013-2017 vehicles due to a software fault that may cause the date and time for the emergency call system (eCall) to differ from the actual date and time, potentially relaying an inaccurate vehicle location. For a full list of the affected models visit: https://static.nhtsa.gov/odi/rcl/2019/RMISC-19V787-4620.pdf
Consequence: An inaccurate vehicle location may delay emergency responders, increasing the risk of injury.
Remedy: MBUSA has initiated an Over the Air (OTA) remote update. MBUSA will also notify owners, and dealers will check software for a successful OTA or update the communication module software as needed, free of charge. The recall began December 23, 2019. Owners may contact MBUSA customer service at 1-800-367-6372. MBUSA's number for this recall is 2019120008.
Size-standard part numbers — verify your connector type before buying. Rear blades are model-specific; check the package's vehicle list.
Fuel economy figures are EPA data via fueleconomy.gov (median across matching trims). Performance figures are compiled estimates for the 2015 Mercedes-Benz S600 6.0L V12 BiTurbo M279 and can vary by trim.
🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Lexus & Toyota Mechanic · 20+ years.