BMW E60 M5 (S85): The Legendary V10—Problems and Maintenance
Summary. The BMW E60 M5 (2005–2010) is the only series-production BMW ever built with a ten-cylinder engine. The S85 V10 makes 500 hp and revs to 8,250 rpm, but it demands strict maintenance. The main risks: rod bearing wear, throttle actuator failure, and degradation of the SMG hydraulic pump. Before you buy, diagnosing these systems is mandatory.
The Problem
You climb into an E60 M5, fire up the V10—and hear a knock at idle that has no business being there. Or you press the throttle and the car drops into limp mode with revs limited. Familiar scenarios for owners of this legendary sedan: the S85 is unique in character, but it demands attention and regular spending. Skip the preventive work and the engine can destroy itself—and the repair bill can rival the price of the car.
Symptoms
- Knocking at idle and through the 1,600–2,000 rpm range
- Limp mode with a check engine light on the dash
- Sluggish, imprecise SMG shifts
- Oil traces on the valve cover and around the engine
- Oil smell in the interior
Causes
Rod bearing wear is the most serious S85 problem. Under high loads and high rpm, the oil film on the bearings breaks down and metal meets metal. The knock sets in, and if you keep driving, the bearings spin—a connecting rod lets go, and the engine is due for a rebuild.
Throttle actuator failure. The S85 runs individual throttle bodies, one per cylinder, each actuated by its own servo motor. When one fails, the DME drops the engine into limp mode and logs codes CDC0, 2B57, 2B21.
SMG hydraulic pump degradation. After 62,000–75,000 miles, the pump loses output. Shifts turn sluggish, the gearbox hesitates, and in neglected cases it refuses to change gears at all.
Valve cover gasket leaks. The rubber loses elasticity over time, oil seeps out, and fouls the spark plugs and wiring.
The Fix
Rod bearing replacement every 56,000–62,000 miles is required maintenance, not a suggestion. Ignore it and the engine tears itself apart. Prevention always costs less than a rebuild.
At 62,000–75,000 miles, plan on replacing the SMG hydraulic pump and accumulator. These are wear items with a finite service life. Replace them before they fail—otherwise the car may simply refuse to move.
Use the correct oil volume—it’s critical to this engine’s longevity:
| Engine Version | Oil Capacity |
|---|---|
| Before March 2007 | 9.3 liters |
| After March 2007 | 9.85 liters |
At the first sign of an oil leak, replace the valve cover gasket. It’s an inexpensive job that prevents fouled spark plugs and damaged wiring.
Pre-Purchase Checklist
- Listen to the engine cold: a bearing knock points to rod bearing wear
- Scan for codes CDC0, 2B57, 2B21—a sign of a failing throttle actuator
- Judge how cleanly the SMG shifts: delays and jerks point to a worn hydraulic pump
- Inspect the valve covers and the block mating surfaces for oil traces
The Bottom Line
The S85 is the only series-production V10 in BMW history, built on Formula 1 technology. It shares no parts with any other BMW engine, which makes sourcing components harder—but that uniqueness is exactly what makes the E60 M5 special. The engine also became the basis for the S65 V8 in the E90 M3. Buy one only if you’re ready for regular spending: rod bearings every 56,000–62,000 miles and SMG service are mandatory budget items. Get a specialist diagnosis before you buy—and a well-maintained M5 will reward you for years.