OVERVIEW
Genuine engine oil-system sealing ring
The N-900-396-03 Genuine VW/Audi O-ring seals the assigned engine oil-system connection on the configurations listed below. The same factory ring appears in more than one original assembly, so identify the precise engine and sealing point before ordering.
The Passat W8 application uses the assigned oil-system/dipstick sealing arrangement. The Audi A4 applications listed here identify the specified O-ring in the original 3.2L oil-pump assembly. This is not a universal dipstick or oil-filter seal for every VW and Audi.
Technical details
- Complete factory number: N-900-396-03.
- Factory nominal size: 9.25 × 1.78 mm.
- Design: separate sealing O-ring for the assigned original groove and mating components.
- Quantity supplied: one individual ring.
The nominal size identifies the sealing ring, not its packaged shipping dimensions. Match the complete number and original groove rather than substituting another ring of roughly similar appearance. Material formulation and packaged weight are not specified here.
Common reasons to replace
- The ring is cut or nicked during removal or installation.
- The original ring has hardened, flattened or lost elasticity.
- The ring is missing or an incorrect substitute was installed.
- Inspection identifies a damaged ring at the assigned leaking connection.
- The factory procedure requires a new seal after the joint is disturbed.
Check the mating component, sealing groove and surrounding area before repair. Oil near a joint can originate elsewhere; confirm the leak source. A new O-ring cannot repair a cracked housing, scored sealing surface or distorted component.
Vehicle fitment
Match the engine, body generation and original sealing location shown below. Different seals within the same oil-system assembly are not interchangeable simply because they appear beside one another in a diagram.
| Vehicle | Model years | Engine | Configuration | Application restrictions |
|---|---|---|---|---|
| Volkswagen Passat | 2002 | 4.0L W8 gasoline; PR M3E | B5.5 sedan or wagon; 4Motion; 5-speed Tiptronic automatic | Original W8 oil-system/dipstick sealing connection assigned N90039603; 9.25×1.78 mm. Excludes other Passat engines and different dipstick seals. |
| Audi A4 | 2008 | 3.2L FSI gasoline V6; PR D2G | B7 sedan or Avant; original 3.2L oil-pump assembly; Original engine oil-system connection | Assigned 9.25×1.78 mm O-ring in 3.2L D2G oil-pump assembly. Excludes 2.0T and other O-rings in the same assembly. |
| Audi A4 | 2009 | 3.2L FSI gasoline V6; PR D2G | B7/8H Cabriolet; quattro; 6-speed Tiptronic automatic; original engine oil-system connection | B7 Cabriolet D2G 3.2L oil-pump assembly only. Excludes B8 sedan/Avant, S4 and 2.0T Cabriolet under this row. |
Installation guidance
Follow the factory service procedure for the exact oil-system connection. Keep open oil passages clean, remove the old ring without scratching the groove and inspect the receiving surfaces. Use the lubricant and installation method specified for the joint; avoid twisting, pinching or stretching the new ring unnecessarily.
Seat the mating component squarely and follow its prescribed fastening sequence. Do not use excess torque to compensate for a damaged seal or housing. Restore the assembly, check the oil level as required and perform the specified post-service leak checks.
Ordering information
Supplied as one genuine O-ring. Dipstick, guide tube, oil pump, housing, oil filter, fluids and a complete seal kit are not included. Confirm the required quantity and complete factory number for the connection being serviced.