Valve Stem Seal Cummins 3921640 | J921640, 3921639, 3901097, 4895347

High-Quality Valve Stem Seal for Cummins 4BT & 6BT Engines

The valve stem seal is a critical component in your engine’s valvetrain, designed to prevent engine oil from leaking into the intake and exhaust ports. By maintaining a precise barrier, this seal prevents oil consumption, reduces blue exhaust smoke, and protects the combustion chamber from carbon buildup.

Product Features & Specifications

• Precise Fitment: Engineered specifically for Cummins B-series engines, ensuring a reliable and secure seal around the valve stem.
• Durable Construction: Manufactured from high-grade elastomeric materials designed to withstand extreme temperatures and constant exposure to engine oil.
• Dimensions: 8 mm x 12 mm / 17 mm x 12 mm.
• Application: Suitable for older-type Cummins 4BT 3.9L and 6BT 5.9L engines (typically manufactured up to 2003).

Engine Compatibility

This valve stem seal is compatible with the following heavy-duty diesel engines:

• Cummins 4BT (3.9L)
• Cummins 6BT (5.9L)

Please verify your engine serial number (ESN) or cross-reference part numbers before ordering to ensure correct fitment.