The BMW M5 is not just a performance car. It's a benchmark — a vehicle that has repeatedly redefined what a high-performance sedan can be since its introduction in 1984. From the hand-built S38 straight-six of the original E28 to the 627-horsepower twin-turbocharged S63 in the current generation, every M5 has been defined by its engine. So when one of these extraordinary powerplants needs replacement, the decision deserves serious thought. Buying a used BMW M5 engine is one of the most significant purchases you can make in the performance car repair world. The engines are complex, expensive when new, and performance-critical. Done right, sourcing a quality used M5 engine can save you $10,000 or more compared to new OEM pricing — while restoring the full capability of one of the world's great driving machines.
The M5 Engine Lineage: Understanding What You're Replacing
Before you can buy the right engine, you need to understand which one your M5 uses. BMW's M division has produced five distinct engine families across M5 generations:
S38 B36 / B38 (E28 & E34 M5, 1984–1995) The original M5 used a naturally aspirated inline-six developed directly from BMW's racing program. The S38 B38 in the E34 (3.8L) produces 340 horsepower in European specification. These engines are increasingly rare, primarily found in restoration projects, and command premium prices even in used condition due to scarcity.
S62 (E39 M5, 1999–2003) Widely considered one of the greatest BMW engines ever produced, the S62 is a 5.0L naturally aspirated V8 producing 394 horsepower. It features individual throttle bodies, a high 11.0:1 compression ratio, and BMW's VANOS variable valve timing on both camshafts. Used S62 engines are actively sought after and typically command $3,500–$7,000 depending on condition.
S85 (E60 M5, 2005–2010) The S85 is the most exotic production BMW engine ever fitted to a road car: a 5.0L V10 derived from Formula 1 technology, producing 507 horsepower at a screaming 8,250 RPM redline. It is also the most technically demanding M5 engine to own, with known issues around rod bearings and throttle actuators. Used S85 engines with documented maintenance history are valuable; uninspected units carry real risk.
S63 B44 / B44T4 (F10 and F90 M5, 2012–present) The shift to forced induction began with the F10 generation. The S63 is a twin-turbocharged 4.4L V8 that started at 552 horsepower and has since grown to 627 hp in the latest Competition specification. It's the most available used M5 engine on the current market, with growing supply as F10-generation M5s age into their second and third owners.
The S85 V10: The Most Complex Engine Replacement Decision
No discussion of used BMW M5 engines is complete without honest attention to the S85 V10. This engine is extraordinary in the way that only naturally aspirated, high-revving V10s can be. It is also, candidly, the most demanding engine to buy used without thorough vetting.
Rod Bearing Wear The S85's rod bearings are its most discussed weakness. Under hard driving conditions — or when oil change intervals were stretched — the rod bearings can wear prematurely, leading to catastrophic engine failure. When evaluating any used S85, the single most important question is whether rod bearing inspection and/or replacement has been performed. On an engine with 50,000+ miles and no documented bearing service, this should be factored into the purchase price or completed immediately after installation.
SMG to Manual Conversions Many E60 M5s came with the sequential manual gearbox (SMG), and some owners have converted to traditional six-speed manual transmissions. When replacing the S85 in an SMG car, the engine's flywheel and mounting hardware are configured differently than the rare manual specification confirm compatibility before purchasing.
Throttle Actuator Condition The S85 uses ten individual electronic throttle actuators — one per cylinder. These are prone to failure as they age and cost roughly $300–$600 each when replaced. A reputable used engine seller will note the condition of the throttle actuators as part of their inspection process. Despite these considerations, a properly vetted S85 with documented maintenance history is worth buying. There is no modern turbocharged engine that replicates the S85 experience the reward is unique.
The S63: The Modern Choice with Fewer Complications
For owners of F10 and F90 generation M5s, the S63 engine family represents a more forgiving used purchase. The twin-turbocharged architecture delivers more predictable power delivery, the engine is less sensitive to occasional maintenance lapses than the S85, and growing supply keeps pricing more competitive.
The S63 is not without its own considerations:
Oil Separator (Catch Can) Buildup The S63's crank case ventilation system can accumulate carbon deposits in the intake manifold and intake valves — a common issue on direct-injection turbocharged engines. For a used S63, ask about carbon cleaning service history.
Turbocharger Heat Soak The S63 uses a "hot vee" turbocharger configuration where both turbos sit inside the engine's V. This creates significant heat concentration. Heat shields and oil feeds to the turbos should be inspected carefully on any used S63.
Coolant Pump Reliability The S63 uses an electric coolant pump that can fail, particularly on higher-mileage units. This is a known service item that's relatively inexpensive to replace — but worth confirming the status of before finalizing a used engine purchase.
Pricing Guide for Used BMW M5 Engines
The M5 engine market spans an enormous range, reflecting both the age of the vehicles and the exotic nature of each powerplant:
Engine Generation Horse power Used Market Range S38, B38, E34, M5, (1991–95)340 hp$4,000–$9,000 S62 5.0L V8E39, M5 (1999–2003)394 hp$3,500–$7,500S85 5.0L V10E60, M5 (2005–10)507 hp$4,500–$10,000, S63 4.4L TT V8F10 M5, (2012–16)552 hp$5,000–$12,000, S63 4.4L TT V8F90 M5 (2018–present)600–627 hp$8,000–$16,000+
These ranges reflect inspected, documented units. Uninspected "pulls" from salvage yards will often appear cheaper but carry commensurate risk for an engine of this complexity.
The Documentation Standard for Performance Engine Purchases
When you're spending anywhere from $4,000 to $16,000 on a used BMW M5 engine, documentation is not optional — it's the foundation of the transaction. A reputable supplier should be able to provide:
Donor vehicle VIN and verifiable mileage history
Compression test results across all cylinders
Oil analysis or oil condition assessment where possible
For S85: specific documentation of rod bearing inspection
For S63: documentation of turbocharger condition and oil separator status
Written warranty coverage specifying what's covered and for what period
Any supplier who pushes back on providing documentation is not operating at the standard that a purchase of this magnitude deserves.
The Warranty Question Is Even More Critical Here
Performance engines like the S85 and S63 make the warranty conversation uniquely important. The cost of a failure in one of these engines is not just inconvenient — it can be financially devastating. An extended warranty from a reputable supplier who has inspected the engine and stands behind it provides genuine value. Look for minimum coverage, with strong suppliers offering 4 year / 40,000-mile protection. For M5 owners who bought the car because they value the driving experience, the warranty is what lets you actually use it without constant anxiety.
Installation: Why You Need a Specialist
BMW M engines — the S85 in particular — are not standard-shop repairs. The S85's SMG hydraulic system, individual throttle actuators, and high-compression naturally aspirated setup require familiarity that general mechanics may not have. The S63's turbocharger oil feeds and heat management components need careful attention. Work with an independent BMW specialist or M-certified technician for M5 engine replacement. The labor investment is justified by the engine's complexity, and a proper installation is what gives your warranty the best chance of never being needed.
Is a Used BMW M5 Engine Worth It?
Absolutely with the right approach. The M5's performance envelope cannot be replicated by a comparable-displacement non-M engine. If you've committed to owning and driving an M5, you've already chosen an extraordinary machine that deserves an extraordinary powerplant. A properly sourced, documented, and warranted used M5 engine restores everything that makes these vehicles special. The S62 remains one of the all-time greats for a reason. The S85 V10 is an experience unavailable anywhere else in a production road car. And the S63, despite its forced-induction architecture, has earned its reputation as a genuinely world-class performance engine.
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