BMW E60 M5 S85B50 Engine: A Quick Breakdown of the Legendary V10
Quick Summary
S85B50 is BMW’s only production V10, fitted to the BMW M5 (E60) and BMW M6 (E63) from 2005 through 2010. It makes 507 hp and 384 lb-ft, good for 0–60 mph in 4.7 seconds. Its main weakness is rod bearing wear—new bearings are due every 50,000 miles. Keep the schedule and the engine will cover 124,000–186,000 miles without a rebuild. This guide is for E60 M5 owners and buyers.
The Problem: Thrills and Responsibility
Drop into an E60 M5, plant your foot, and the V10 spins to 7,750 rpm with a sound you can’t mistake. But owning this engine isn’t just about emotion. The S85B50 is sensitive to oil quality, and ignoring the service schedule gets expensive fast. Miss its weak spots and you could be looking at a full engine rebuild.
Symptoms
- Metal shavings in the oil or stuck to the oil filter
- Knocking, clicking, or rattling from the VANOS area on cold starts
- Oil leaks around the VANOS units
- Dropping oil pressure
- Poor running at low rpm
- Fault codes and power loss from a broken wire on the VANOS solenoid valve
Causes
Rod bearing wear is the best-known S85B50 problem. The factory calls for new bearings every 50,000 miles, and plenty of owners skip it. Worn bearings shed metal shavings, drop oil pressure, and in the worst case seize the engine.
VANOS failure traces to a hardened piston seal and wear in the needle bearing and washer. Metal shavings can also get into the VANOS solenoid valve and break its seal.
The aluminum block has no cylinder liners, so it’s sensitive to oil quality and wear—a design trait that demands maintenance discipline.
The Fix: Schedule and Prevention
Rod bearing replacement every 50,000 miles is mandatory prevention. Most S85B50 failures trace back to bearing wear, and the job costs a fraction of a rebuild.
Check the VANOS at the first noise, leak, or fault code. Diagnosis covers the seals, the needle bearing, and the solenoid valve. Usually new O-rings and a flushed valve solve it.
If you find shavings in the oil, act immediately:
- Drain the oil, drop the pan, and inspect it for debris
- Check the bearings and the crankshaft
- Minor damage: new bearings and a flush
- Severe cases: regrind the crankshaft and replace the pistons
The sooner you catch the problem, the cheaper the repair.
Prevention and Buyer’s Checklist
- Check the bearings: ask the seller when they were last done. No documentation? Assume they’ve never been replaced
- Evaluate the VANOS: start the engine cold, listen for knocks, check for oil leaks
- Inspect the oil for shavings: pull the oil filler cap, check the level and the smell
- Confirm the service history: regular oil changes every 4,300–6,200 miles signal a car that’s been cared for
- Budget for a bearing job right after purchase if there’s no documentation
Tuning: From 507 to 650+ hp
Individual throttle bodies and sophisticated electronics let you add power without drastic surgery. The most popular route is a supercharger.
The ESS S85 VT2 kit with a Vortech V3Si supercharger takes output to 650 hp. Reliability holds if you prep the engine first: new bearings, an upgraded cooling system, and an oil cooler.
The S85B50 also spawned the 4.0-liter V8 S65B40 fitted to the BMW M3 (E90/E92/E93). From the V10 it inherited the aluminum block, VANOS, and individual throttle bodies.
Without forced induction you can reach 550–570 hp—a tune, sport exhaust and intake, and cylinder head work.
The Bottom Line
The S85B50 is an engineering masterpiece that demands a responsible owner. Bearings every 50,000 miles, VANOS checks, and regular oil inspection are non-negotiable. Keep the schedule and the engine will cover 124,000–186,000 miles without a rebuild. Find an E60 M5 with a documented history, and you’re buying pure emotion.
📖 Deep dive: S85B50 Engine — the full technical study, with control unit specs, the lubrication system, and engineering nuances.