3900709 3904353 Cummins Crankshaft Oil seal For 4BT 6BT Engiens

The 3900709 & interchangeable 3904353 are top-selling front crankshaft oil seals for Cummins 4BT/6BT engines. Double-lip FKM rubber with steel skeleton delivers reliable high-temperature oil sealing. Ideal aftermarket replacements for trucks, construction machines and generators, widely searched by global diesel repair shops.

Key Features:

✅TC double-lip sealing structure with built-in stainless steel garter spring, stable radial pressure to stop oil seepage and dust intrusion

✅Dual rubber material options: standard NBR for general use, high-performance FKM for high-temp & diesel corrosion resistance

✅One-piece cold-rolled steel skeleton integrated with rubber, anti-deformation, perfect fit on crankshaft housing

✅Wide temperature tolerance: NBR -30℃~150℃; FKM up to 180℃, compatible with engine oil, diesel and hydraulic oil

✅Anti-wear lip surface, low friction, long service life under continuous heavy-duty operation

Application:

✅Commercial Trucks:Light/medium cargo trucks, logistics vans, long-distance & cold-chain delivery vehicles

✅Passenger Vehicles:Minibuses, coaches, school buses with 6BT/ISDe engines

✅Construction Machinery (Core Application):Loaders, 6–12t excavators, road rollers, pavers, cement mixers, 5–10t forklifts

✅ Industrial Power Units:Standby diesel generators, marine auxiliary engines, mining air compressors & crushers

Why Choose US?

✅Professional China-based Cummins parts supplier

✅Genuine Cummins quality, strict factory inspection

✅Direct factory supply with competitive cost advantage

✅Stable stock & fast global delivery

✅Technical matching support for all B-series engines