OVERVIEW
Genuine VW/Audi rear crankshaft seal with flange, part number 06A-103-171-A. Mounted at the transmission end of the specified engine, this assembly carries the seal around the rear of the rotating crankshaft and closes the corresponding rear crankcase opening. It is commonly called the rear main seal or rear sealing flange.
Technical details
- Original part number: 06A-103-171-A / 06A103171A.
- Rear crankshaft sealing assembly with the flange and installed circular seal shown in the original photo.
- Engine-oil sealing component at the transmission side of the engine, not a transmission input-shaft seal or front crankshaft seal.
- Flange shape, mounting pattern and engine application must match the original assembly.
- Bolts, sealant, flywheel/flexplate and clutch components are not included.
- For the Mk5 2.0T rows, fitment is restricted to the timing-belt FSI engine. Later timing-chain TSI engines require their own cataloged sealing flange.
Common reasons to replace
Replace the assembly when diagnosis confirms leakage from the rear crankshaft sealing area, a damaged seal lip or a damaged flange. Oil at the lower bellhousing area can prompt inspection, but leakage from higher on the engine or another nearby joint must be ruled out before identifying the rear main seal as the source.
On a manual-transmission vehicle, oil that reaches the clutch friction surfaces may contribute to clutch contamination or slipping. Inspect affected clutch components separately. Also check crankcase ventilation and operating pressure, because an unresolved ventilation fault can contribute to recurring leakage after seal replacement.
Installation and service notes
Follow the engine-specific transmission, flywheel/flexplate and sealing-flange removal procedure. Support the drivetrain correctly and inspect the crankshaft sealing surface and block mating face before installation.
Use the prescribed alignment and installation tool to position the seal and flange without folding or damaging the sealing lip. Follow the instructions supplied with the actual seal design for preparation and lubrication; do not apply a generic oiling method to every rear-main-seal type.
Apply only the specified flange-joint sealant where the service procedure requires it, observe the prescribed tightening order and replace companion single-use hardware as directed. Check the repaired area for leakage after reassembly and normal operating checks.
Fitment
| Vehicle | Model years | Engine | Body and transmission | Restrictions |
|---|---|---|---|---|
| Volkswagen GTI | 2002 | 1.8L turbo gasoline | Mk4 hatchback; Automatic. | Match original rear seal/flange. |
| Volkswagen GTI | 2000 | 1.8L turbo gasoline, AWD engine code | Mk4 hatchback, front-wheel drive; 5-speed manual. | AWD is the engine code in this row, not an all-wheel-drive designation. |
| Volkswagen GTI | 2002–2005 | 1.8L turbo gasoline, AWP | Mk4 hatchback, front-wheel drive; 5-speed automatic. | Match AWP engine and original flange. |
| Volkswagen Jetta | 2002–2005 | 1.8L turbo gasoline, AWP | Mk4 sedan, front-wheel drive; 5-speed manual. | Excludes the later Mk5 Jetta. |
| Volkswagen Jetta GLI | 2004.5–2005 | 1.8L turbo gasoline, AWP | Mk4 sedan, front-wheel drive; 6-speed manual. | Mk4 GLI 1.8T application; not the later 2.0T GLI. |
| Volkswagen Jetta | 2001–2005 | 2.0L naturally aspirated gasoline | GLS wagon; Match original rear flange. | Four-cylinder wagon application; not a universal 2.0T seal. |
| Volkswagen GTI | 2006–2008 | 2.0L turbo gasoline, BPY FSI | Mk5 hatchback; 6-speed manual or 6-speed DSG. | Timing-belt FSI engine only; excludes later CCTA/CBFA TSI. |
| Volkswagen Jetta GLI | 2006–2008 | 2.0L turbo gasoline, BPY FSI | Mk5 sedan; 6-speed manual or 6-speed DSG. | Timing-belt FSI engine only; excludes later CCTA/CBFA TSI. |
| Volkswagen Golf R | 2012–2013 | 2.0L turbo gasoline, CRZA FSI | Mk6 hatchback, 4Motion; 6-speed manual. | EA113 FSI engine; not the later Mk7 Golf R. |
| Audi A4 quattro | 2006 | 2.0L turbo gasoline | B7 base sedan; Match original rear flange. | Four-cylinder FSI application; not the 3.2L V6. |
| Audi A4 quattro | 2008 | 2.0L turbo gasoline | B7 Avant wagon; Match original rear flange. | B7 FSI engine; excludes later B8 TFSI engines. |
| Audi A4 quattro | 2009 | 2.0L turbo gasoline | B7 Cabriolet; Match original rear flange. | Cabriolet only in this row; not the B8 sedan or Avant. |
| Audi A4 | 2009 | 2.0L turbo gasoline | B7 Cabriolet, front-wheel drive; Match original rear flange. | Cabriolet only in this row; not the B8 sedan. |
Confirm the engine code, original rear sealing flange and chassis before ordering.