Mercedes Sprinter Piston Ring Set – Kolbenschmidt | NCV3 3.0L OM642 Standard 83mm | #6420300024 (2007–2022)

Worn piston rings on a Sprinter OM642 allow combustion gases to blow past the piston into the crankcase and allow oil to migrate past the oil control ring into the combustion chamber — producing a progressive loss of compression, increased oil consumption, and the blue-gray smoke and rough idle that signal ring wear. This is the Kolbenschmidt piston ring set in standard 83mm bore size for NCV3 and VS30 Sprinters equipped with the 3.0L OM642 V6 diesel engine, sold per cylinder for engines with bores at standard dimensions.

What This Part Does

Each piston in the OM642 uses three rings seated in grooves on the piston: a top compression ring that seals combustion gases from passing the piston, a second compression ring that provides secondary sealing and helps scrape oil from the cylinder wall, and an oil control ring assembly that prevents excess oil from reaching the combustion chamber while ensuring the cylinder wall receives adequate lubrication. The rings must maintain spring pressure against the cylinder wall to seal effectively — when they wear, lose tension, or become stuck in their grooves from carbon buildup, their sealing function degrades. The standard 83mm rings are for engines with cylinder bores measuring within the factory standard dimension — engines that have been bored oversize require matching oversize rings.

Common Symptoms of Worn Piston Rings

• Increasing oil consumption between changes with no external leak identified
• Blue-gray smoke from the exhaust, particularly on startup and deceleration
• Loss of compression confirmed by a compression test showing low or uneven cylinder pressures
• Excessive blow-by — oily mist or pressure at the crankcase ventilation outlet
• Black or oil-fouled spark plugs on diesel pre-chamber engines, or oil-fouled injector spray patterns

When to Use

Use during piston replacement, cylinder honing, or engine rebuild when cylinder bores measure within standard 83mm specification. One set required per cylinder — 6 sets for a complete OM642 V6 engine. Always hone the cylinder bores before installing new rings, measure bore diameter, and verify ring end gap per factory specification before assembly.

NCV3 & VS30 OM642 Specific — Engine Verification Required

This ring set is for NCV3 and VS30 Sprinters equipped with the 3.0L OM642 V6 diesel engine with standard 83mm bore dimensions. Engines bored oversize require matching oversize rings. Always measure bore diameter 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)

✔ Standard 83mm bore — verify bore diameter before ordering
✔ Sold per cylinder — 6 sets required for complete V6 engine
✔ Always hone cylinders and check ring end gap before installation

Part Numbers

• Mercedes OEM: 6420300024 / A6420300024 / 642-030-00-24
• Manufacturer: Kolbenschmidt — 800055810000
• SKU: 6420300024 (6 PER ENGINE)