The VW/Audi Oil Approval System
Volkswagen Group certifies oils through a tiered approval system — each specification defines minimum requirements for viscosity, high-temperature high-shear (HTHS) viscosity, detergent package, and long-drain stability. The spec number appears on certified oil bottles (e.g., "Meets VW 502.00"). A 5W-40 oil that doesn't carry the VW approval may have the right viscosity grade but the wrong additive chemistry for your engine's variable valve timing system, turbocharger, and catalytic converter.
Quick Reference: Spec by Engine
| Engine | Models | Required Spec | Viscosity |
|---|---|---|---|
| EA888 Gen 1/2 (2.0T, pre-2017) | B8 A4, Q5, A3 8P/8V early | VW 502.00 | 5W-40 |
| EA888 Gen 3 (2.0T, 2017+) | B9 A4, Q5 Gen 2, A3 8V late | VW 508.00 | 0W-20 |
| 3.0T SC V6 | A6, A7, Q7, B8 S4/S5, SQ5 | VW 502.00 | 5W-40 |
| EA839 3.0T (2017+) | B9 S4, S5, SQ5 Gen 2 | VW 504.00 | 5W-30 |
| 4.0 TFSI V8 | S6, S7, S8, RS7 (C7) | VW 502.00 | 5W-40 |
| 4.2 V8 FSI | R8 V8, RS5 B8, A6 C6 4.2 | VW 502.00 | 5W-40 |
| 2.5T Inline-5 | RS3, TTRS | VW 502.00 | 5W-40 |
| 3.0 TDI Diesel | Q7 TDI, A6 TDI | VW 507.00 | 5W-30 |
What the Spec Numbers Mean
VW 502.00 is the longstanding high-HTHS specification for older turbocharged gasoline engines. HTHS viscosity above 3.5 mPa·s — this means the oil maintains film thickness at the extreme temperatures found in turbocharger bearings and performance engine applications. Most 5W-40 full synthetics meeting 502.00 are appropriate.
VW 504.00 is a mid-HTHS spec (minimum 3.5 mPa·s) allowing long drain intervals with lower-viscosity base. Primarily used in newer naturally-aspirated and lightly-turbocharged applications requiring extended oil change intervals.
VW 508.00 is the ultra-low viscosity spec (HTHS 2.6 mPa·s) for EA888 Gen 3 engines with tighter tolerances and active oil pressure management. 0W-20 viscosity significantly improves cold-start fuel economy and reduces warm-up time. Critical: substituting a 5W-40 502.00 oil in a 508.00-specified engine causes increased carbon buildup on the intake side and higher fuel consumption — the engine is calibrated for the lower viscosity.
VW 507.00 is diesel-specific with low-SAPS (sulfated ash, phosphorus, sulfur) formulation to protect diesel particulate filters. Using a gasoline engine oil in a TDI accelerates DPF clogging.
Oil Change Intervals
Audi's Flexible Service Interval (FSI) system adjusts oil change intervals based on oil quality sensor data, driving style, and temperature history — intervals can reach 10,000 miles or more. Most specialists recommend ignoring the flexible interval and using fixed intervals: 5,000–7,500 miles on performance variants and turbocharged engines, 7,500 miles on standard use B9 and 8V generation cars. The cost of an extra oil change annually is trivial compared to the bearing wear that accumulates in degraded oil.
Brands That Meet VW Specs
Audi does not require Audi-branded oil. Any oil bottle with the VW approval printed on the label (not just "compatible with" — the actual approval number) is acceptable. Common quality options: Liqui-Moly (502.00, 508.00), Castrol Edge (502.00), Motul (502.00), Pentosin (multiple specs). Avoid off-brand oils from suppliers without verifiable spec certifications, regardless of what the seller claims.
What to Ask at Any Oil Change
Before authorizing any Audi oil change at a non-specialist: ask the technician to show you the oil bottle. Verify the VW approval number on the label matches your engine's spec. A service advisor who doesn't know your car's oil spec is a shop that will put conventional 5W-30 in your 3.0T. It happens regularly and the consequences are slow and cumulative.