BMW M5 vs Audi RS7: Rod Bearings vs Oil Screens — Which V8 Fails First?
BMW M5 vs Audi RS7: Rod Bearings vs Oil Screens — Which V8 Fails First?
Reliability Score
Based on owner reports and frequency of repairs.
Published on: Tue Mar 10 2026
BMW M5 vs Audi RS7: Rod Bearings 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 – 617 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 |
| 0–60 | 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: Rod Bearing 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–$15,000.
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 – $4,000 | $2,000 – $3,500 |
| Brakes (Front Axle) | $1,500 – $2,500 | $1,500 – $2,000 |
| Preventive Engine Service | $0 (TU4 less critical) | $500 (Oil Screen Check) |
| Annual Total (Est.) | $4,000 – $6,000 | $3,000 – $5,000 |
Winner on Maintenance Cost: Audi RS7 — marginally 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 — slightly 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.