Oil Consumption on Your Mercedes M278 V8? Rebuild the PCV Separator for $26.
The PCV oil separator on Mercedes M278 (4.0L, 4.6L V8) and M157 (5.5L, 6.0L V8) engines is a known failure point. When the separator fails, oil blow-by enters the intake system, causing oil consumption, blue smoke, and intake oiling. This complete repair kit (OEM ref. 2780100431) includes the diaphragm and all seals needed for a full separator rebuild.
✓ What You Get: Complete PCV oil separator repair kit — diaphragm membrane + all seals — for Mercedes M278 V8 (4.0L/4.6L) and M157 V8 (5.5L/6.0L).
What's Included
- PCV oil separator diaphragm membrane (OEM 2780100431)
- Housing O-rings and seals (complete set)
Why Rebuild Instead of Replace?
- Stops Oil Blow-By: Worn diaphragm allows oil mist to bypass the separator and enter the intake.
- Reduces Oil Consumption: Restores proper crankcase ventilation — oil stays in the crankcase.
- Clears Blue Smoke: Eliminates exhaust smoke caused by ingested oil vapor.
- Saves $200+ vs Assembly: OEM separator assembly $230+; this full rebuild kit costs $26.
- 45-Minute Rebuild: Disassemble separator, replace membrane and seals, reassemble.
Vehicle Compatibility
| Make | Model | Engine |
|---|---|---|
| Mercedes-Benz | S-Class, CL, SL, GL, GLS | M278 4.0L / 4.6L V8 |
| Mercedes-Benz / AMG | S63, CL63, SL63, ML63 | M157 5.5L / 6.0L V8 |
About This Kit
Mercedes M278/M157 PCV oil separator repair kit (OEM ref. 2780100431) provides everything needed for a full separator rebuild on M278 4.0L/4.6L and M157 5.5L/6.0L V8 engines. This is the complete kit version — includes the diaphragm membrane plus all housing seals for a thorough rebuild.
⚠ Verify Part Number Before Ordering: Confirm OEM 2780100431 matches your separator assembly before purchasing.
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Orders ship within 1–2 business days.
Standard delivery:
- USA: Some items ship from our US warehouse and arrive within 3 business days.
- USA-EU: 10–21 business days
- Worldwide: 14–30 business days
Shipping cost is shown at checkout.
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- the product was not in use and has no traces of use: scratches, chips, abrasions, etc.
- the goods are fully completed and the integrity of the packaging is not violated
- retained all labels and factory markings