BMW M6
BMW's first turbo V8 in the M5 — the crossflow exhaust routing between the cylinder banks (hot-V) produces an atypical V8 sound: less primitive burble than the S62 naturally aspirated, more muted growl with turbo whistle in the background. What the S63 loses in character it gains in torque — 680 Nm available from 1,500 rpm, pushing consistently to above 5,000 rpm. The Achilles heel is the con rod bearings: metal swarf in the oil filter on an oil change is the earliest warning sign. Preventive bearing replacement every 80,000–100,000 km is strongly recommended, costing €4,000–6,000. Oil cooler seals weep from 60,000 km; turbocharger oil supply lines coke up with Longlife intervals. Shorten oil changes to 8,000 km and have the bearings done and the result is a robust engine.
Open M flagship with V8 bite
560 hp S63 in a convertible — less fanatical than the E64 M6 V10, but enormous torque and brutal motorway capability. With an Akrapovic exhaust the S63 sounds significantly more emotional. Grand touring character at M level.
Engine Weaknesses 6
Connecting rod bearing shells wear through high revs and turbo boost pressure. Metal particles in the oil filter are the earliest warning sign. Preventive replacement every 80,000–100,000 km for around €2,390 is recommended — compared to €30,000–€50,000 for a replacement engine.
Symptoms: Knocking or hammering engine noises under load and at idle, metal particles in the oil filter or sump, oil pressure warning light, engine no longer revs freely
Manufacturing tolerance fault on the oil pump drive shaft. The shaft can separate from the rotor, causing immediate total oil pressure loss. Affects approximately 696 US vehicles, produced July–September 2012. NHTSA Recall 12V475000.
The rubber lines and plastic T-connectors of the turbo cooling circuit become brittle through permanent radiant heat in the V-valley. Typically first seen from around 100,000 km. A repair kit with silicone hoses and brass T-pieces is the permanent solution.
Symptoms: Dropping coolant level without visible external leak, gurgling after switching off the engine, rising engine temperature, coolant steam from engine bay
Leaking direct injectors allow fuel to drain into the combustion chamber, which passes the piston rings into the oil. Fuel dilution reduces lubrication capacity and considerably accelerates connecting rod bearing wear.
Symptoms: Elevated oil level on the dipstick (fuel smell in oil), increased fuel consumption, cold-start difficulty, measurable fuel dilution in oil analysis report
Valve stem seals harden through extreme radiant heat from the V-valley turbos. Typically appears around 97,000–120,000 km. Repair costs €2,500–€6,000 (UK workshops £3,540–£4,140 with genuine parts).
Symptoms: Blue smoke cloud from exhaust on first acceleration after an idle period, increased oil consumption above 0.5 L/1,000 km, sooty spark plugs
VANOS solenoids build up oil deposits and fail with fault codes. The S63 has four solenoids; VANOS gears can also require replacement. Typically from 80,000–160,000 km.
Symptoms: Engine fault message (camshaft phaser error), limp mode activation, rough running particularly at certain rev ranges, occasional cold-start difficulty
Vehicle Weaknesses 6
The 7-speed DKG GS7D36SG of the M6 F12 Convertible suffers from aged rubber seals in the mechatronics that cause oil loss. Without regular fluid changes, premature mechatronics failure threatens.
The integral active steering of the F12 M6 Convertible fails through sensor faults; the steering wheel sits crooked, servo assistance collapses. Safety-relevant.
The electric folding roof of the F12 M6 Convertible shows age-related hydraulic problems and sensor failures similar to the M3 E93. Hydraulic cylinders leak and microswitches fail.
Optional CCB of the M6 F12 costs €5,000–10,000 to renew. Standard steel brake discs also wear quickly under S63 torque and vehicle weight.
The folding roof of the F12 M6 Convertible is subject to mechanical wear on hinges, hydraulic lines and pump. Early F12 build years had the most teething issues.
F12/F13 regularly show worn springs and shock absorbers. Rubber mounts in the suspension are a weak point, more heavily stressed in the heavier convertible.
Reports & Tests
13 owner complaints filed with NHTSA (2012–2018). Most reported: Engine (5), Electrical (5), Body Structure (4).