Mercedes Sprinter Crankshaft Main Bearing Kit 0.25mm Oversize – Kolbenschmidt | NCV3 3.0L OM642 | #6420331901KIT025 (2007–2022)

When the OM642's crankshaft journals have been worn beyond standard clearances and require precision grinding to restore a true, round surface, standard-size bearing shells will not restore proper oil film clearance — running undersize journals on standard shells is the fastest way to destroy a freshly rebuilt bottom end. This is the Kolbenschmidt crankshaft main bearing kit in 0.25mm oversize for NCV3 and VS30 Sprinters equipped with the 3.0L OM642 V6, for use after crankshaft main journals have been precision-ground 0.25mm undersize.

What This Part Does

The 0.25mm oversize main bearing shells are dimensioned with a thicker backing to compensate for the material removed when grinding the crankshaft journals 0.25mm undersize. They maintain the correct oil film clearance on reground journals — restoring the hydrodynamic pressure boundary that protects the crankshaft from metal-to-metal contact under full combustion load. When journals develop scoring, taper, or out-of-round wear beyond standard tolerance, precision grinding to 0.25mm undersize restores a true surface, and these matching oversize shells restore the correct clearance.

Common Reasons for Oversize Bearing Selection

• Crankshaft journals found scored, tapered, or out-of-round during engine teardown
• Main bearing knock confirmed and journals measured below standard specification
• Engine rebuild where crankshaft has been sent for precision grinding to 0.25mm undersize

When to Use

Use only after crankshaft main journals have been precision-ground 0.25mm undersize. Always confirm journal diameter with a micrometer and verify clearances with plastigauge — never assume journals are exactly 0.25mm undersize without measurement.

NCV3 & VS30 OM642 Specific — Engine Verification Required

This bearing kit is for NCV3 and VS30 Sprinters equipped with the 3.0L OM642 V6 diesel engine. Always verify your engine code before ordering.

Fitment

• 2007–2018 Mercedes-Benz / Dodge / Freightliner Sprinter 2500 / 3500 – 3.0L OM642 (NCV3)
• 2019–2022 Mercedes-Benz Sprinter 2500 / 3500 – 3.0L OM642 (VS30)

✔ 0.25mm oversize — for use only after journals have been precision-ground
✔ Always verify journal diameter with micrometer and confirm clearances with plastigauge

Part Numbers

• Mercedes OEM: 6420331901 / A6420331901 / 642-033-19-01
• Manufacturer: Kolbenschmidt
• SKU: 6420331901KIT025