BMW M5 vs Audi RS7: Performance & Reliability Comparison
"Choosing between the BMW M5 and the Audi RS7 is a decision that could save Eor cost Eyou thousands. This side-by-side comparison reveals the real reliability winner, with hard data on failure rates and ownership costs."
Engine
7/10
Gearbox
7/10
Electric
6/10
Total Risk
4/10
Quick Verdict
Buy with CautionExpect significant running costs. Manageable if preventative maintenance is done.
Reliability Verdict
The BMW M5 (S63TU4) and Audi RS7 (4.0T) are the two most capable super-saloons on the market. Both have one catastrophic failure mode that demands proactive attention. BMW's rod bearings are preventable with a scheduled service. Audi's turbo oil screens are preventable with an oil change frequency increase. The Audi's catastrophic failure cost is generally lower; the BMW's performance payoff is higher.
In This Guide
BMW M5 vs Audi RS7: BMW M5 Reliability & Real Costs vs Oil Screens
Two twin-turbo V8 super-saloons. Both with over 600 horsepower. Both German-engineered, brutally fast, and surprisingly usable as family cars.
The BMW M5 F90 runs the S63TU4. The Audi RS7 C8 runs the EA825 4.0T.
Both have a catastrophic single-point failure mode that will destroy the engine if ignored.
We are going to tell you exactly what those failure modes are, what they cost, and which car is cheaper to own over 100,000 miles.
1. The Engines: Technical Overview
| Specification | BMW M5 F90 | Audi RS7 C8 |
|---|---|---|
| Engine | S63TU4, 4.4L TT V8 | EA825, 4.0T TT V8 |
| Power | 600 E17 hp | 591 hp |
| Torque | 553 lb-ft | 590 lb-ft |
| Layout | Hot-V (Turbos in Valley) | Hot-V (Turbos in Valley) |
| Transmission | 8-speed TCU (M-Steptronic) | 8-speed ZF8 |
| 0 E | 3.1 seconds | 3.5 seconds |
Both use a “Hot-V” layout. Both suffer from the thermal consequences of that design.
2. The BMW Problem: BMW M5 Reliability & Real Costs Wear
As detailed in the BMW S63 Engine Reliability Guide, the S63TU generation has documented rod bearing wear.
The S63TU4 (F90) significantly improves on the TU’s bearing design:
- Revised oil clearances
- Improved rod metallurgy (stronger rods)
- Quasi-dry-sump oiling prevents starvation under lateral G-loads
F90 M5 Rod Bearing Risk: Substantially lower than F10 M5. Forum consensus is that stock F90s are not showing bearing failures at 60k miles. The danger returns primarily with aggressive tuning (700+ hp builds).
The BMW risk in 2024: The F90 S63TU4 is a genuinely improved engine. The rod bearing scare that tormented F10 owners is reduced significantly on the F90.
3. The Audi Problem: Turbo Oil Screen Clogging
The Audi EA825 Hot-V has its own thermal failure mode: the turbo oil feed screens.
Each turbocharger has a small mesh screen in its oil supply line. In the hot-V, this screen is exposed to extreme heat. Oil cokes (bakes into sludge) onto the screen, restricting flow.
The Consequence:
- Oil starvation to turbo bearings.
- Turbo shaft play, audible bearing noise.
- Full turbo seizure. Metal shards enter engine.
- Engine contamination or destruction.
Cost: Turbo pair replacement is $8,000 E5,000.
The Fix: Change oil every 5,000 miles (not 10,000 as Audi recommends). Preventive oil screen cleaning/replacement during any major service.
The newer EA825 has improved oil routing vs the older EA824, but the core hot-V thermal environment remains.
4. maintenance cost Comparison
| Service | BMW M5 F90 | Audi RS7 C8 |
|---|---|---|
| Oil Change (5,000 miles) | $200 (Indie) | $180 (Indie) |
| Annual Service | $2,500 E,000 | $2,000 E,500 |
| Brakes (Front Axle) | $1,500 E,500 | $1,500 E,000 |
| Preventive Engine Service | $0 (TU4 less critical) | $500 (Oil Screen Check) |
| Annual Total (Est.) | $4,000 E,000 | $3,000 E,000 |
Winner on Maintenance Cost: Audi RS7 —arginally cheaper, simpler service requirements.
5. Technology & Daily Usability
- BMW M5: Raw driver focus. Switchable AWD. More athletic chassis feel.
- Audi RS7: Quattro AWD permanent. Better infotainment (MMI vs iDrive). More prestige on exterior styling.
- Interior quality: The RS7’s interior is subjectively more luxurious. The M5 feels more purposeful.
- Practicality: RS7 is a fastback —lightly more rear headroom. M5 has a conventional trunk.
6. Reliability Verdict
| Category | BMW M5 F90 | Audi RS7 C8 |
|---|---|---|
| Engine Failure Risk | Low (TU4) | Medium (Oil Screen) |
| Worst-Case Failure Cost | $25k (Old S63TU) / $15k (TU4) | $15k (Turbo + Engine) |
| Annual Maintenance | Higher | Lower |
| Long-Term Outlook | Good (TU4 improved) | Good (with oil discipline) |
| Overall Reliability Score | 7.8/10 | 8.0/10 |
Verdict: Both cars are strong long-term options if maintained correctly. The RS7 is slightly more predictable. The M5 is slightly more rewarding to drive.
7. Final Recommendation
Choose BMW M5 F90 if: Driving dynamics and performance experience are paramount. You will service oil every 5,000 miles.
Choose Audi RS7 C8 if: Luxury, technology, and slightly lower maintenance costs matter. You prefer a more refined daily driver.
Both cars: Oil changes at 5,000 miles. No exceptions.
Related Resources
- BMW S63 Engine Reliability
- BMW M5 F90 Reliability & Real Costs
- BMW M8 vs Porsche 911 Turbo Comparison
The Reality Layer: What Owners Underestimate
Buying a BMW is often driven by emotion, but keeping it on the road requires cold, hard logic. The dealership service center will not volunteer this information, but specialist independent mechanics know the truth:
- The Component Labor Trap: Engineering density means simple parts (sensors, plastic coolant fittings) require days of labor to reach. A $50 part often results in a $3,000 labor bill.
- The “Lifetime Fluid” Myth: Manufacturers claim transmissions and differentials use “lifetime” fluids to keep estimated maintenance costs artificially low for the first owner. To avoid a $10,000+ rebuild, you must change these fluids every 40,000 miles.
- Cascading Failures: When an air suspension strut leaks, the compressor burns out trying to keep the car level. Ignoring a warning light for 48 hours on a BMW can easily double the final repair invoice.
Caution
The Worst-Case Scenario: If you suffer a catastrophic failure without a comprehensive warranty or a dedicated $10,000+ emergency repair fund, you will be forced to sell the vehicle mechanically totaled at a massive loss.
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The Final Decision: Worth It?
Worth it if:
- You have a trusted, brand-specialized independent mechanic.
- You maintain a strict $5,000-$10,000 liquid repair reserve.
- You value the driving experience over strict financial rationality.
Not worth it if:
- You are stretching your budget just to afford the purchase price.
- You rely exclusively on the dealership network for out-of-warranty maintenance.
- You expect Toyota-like reliability and predictable ownership costs.
Related Intelligence
Executive Buying Advice
Choose the BMW M5 for driving experience, Audi RS7 for interior technology and practicality. Both require strict oil change schedules. The BMW requires proactive rod bearing service. The Audi requires oil screen attention on pre-2018 EA825 units.
