DRIVEDEX / Mercedes-Benz / S-Class
2007–2013
Mercedes-Benz S-Class
5.5L V8 (M273) M273 Sedan (W221)
Proper V8 S-Class luxury — Airmatic and intake flaps are where the money goes, so check both first.
Engine Oil
Viscosity‼
✓ verified
src: MB BeVo 229.5 sheet + Motor Reviewer M273 specs
Capacity (with filter)
8.5 L✓ verified
Yes, nine quarts — don't short-fill it like an M272
src: Motor Reviewer M273 + MBWorld/owner's manual quotes
Oil filter
✓ verified
OEM A 000 180 26 09 — M273 shares the M272 element
src: FCP Euro HU718/5x listing + Pelican W221 oil kits
Drain plug torque‼
— in verification queue
Being confirmed
Fluids
Transmission
✓ verified
src: FCP Euro 722.9 guide
ATF spec & service‼
✓ verified
Red and blue are NOT mixable — check build date before service
src: Blauparts fluid guide + FCP Euro 722.9 guide
Coolant‼
✓ verified
NEVER mix with pink MB 325.5
src: MB BeVo 325.0 sheet + Blauparts coolant guide
Brake fluid‼
✓ verified
src: MB BeVo 331.0 sheet + genuine fluid listings
Filters & Ignition
Engine air filter
◐ pending
Left and right elements, replace as a pair
src: Pelican/FCP M272-M273 airbox design + Benzworld W221 DIY
Cabin filter
— in verification queue
Being confirmed — replace with Service B
Spark plugs
◐ pending
One plug per cylinder on the M273 — OEM cross A 004 159 49 03
src: Genuine MB/NGK M272-M273 listings + AutohausAZ
Electrical
Battery
◐ pending
2007–09: aux in trunk + starter battery under hood; 2010+: aux under dash. AGM only
src: MBWorld W221 aux battery thread
Key fob battery
◐ pending
src: MB of Fresno key fob guide
Wheels & Wipers
Lug bolt torque‼
130 Nm◐ pending
Some long-bolt fitments spec 111 lb-ft (150 Nm) — verify bolt length before torquing
src: Ricks Free Advice MB torque table
Tire pressure
— in verification queue
Use the driver's door-jamb placard
Wiper blades
— in verification queue
Being confirmed
Service
Oil change interval
◐ pending
src: MB maintenance schedule (dealer guides)
Fuel
✓ verified
src: MBUSA fuel FAQ / owner's manual
Service reminder reset
— in verification queue
Being confirmed
🔧 Mechanic's Notes
- Airmatic is standard and it's the W221's main money pit: strut/air-spring leaks, valve block, and compressors that die because a leak overworked them. A corner that sags overnight = start hunting leaks, and replace the cause with the compressor.
- Early cars (2007–08 builds) can carry the M273 idler-gear wear from the 2004–2008 window — improved parts arrived from late 2006, but recurring P0016–P0019 says pull the timing cover conversation forward.
- The V8's intake manifold flaps gum up with carbon and break their operating levers — rough idle, power loss, check-engine. Common enough to budget for on a high-miler.
- Cam-plug oil leaks at the back of the heads affected engines built before mid-2008; oil on the bellhousing area on an early car is usually those plastic plugs, not the rear main.
Field patterns from a working mechanic — diagnose your own car before buying parts.
Open Recalls
Checking NHTSA…
Sources shown per value. Specs can vary by build date, market and trim — for anything critical (torque, fluids), confirm against YOUR owner's manual or door sticker before wrenching. Spotted an error? — corrections jump the queue.