Product Introduction C6644716 Rear Crankshaft Oil Seal is a critical rotary sealing component fitted at the rear end of the crankshaft on 15NNS6B530A engine assembly. It forms a tight barrier around the rotating crankshaft flange to retain engine lubricating oil inside the crankcase and stop oil from leaking toward the flywheel housing. This aftermarket replacement seal resolves persistent oil seepage, clutch contamination and excessive lube consumption caused by rubber lip hardening, garter spring relaxation and surface scoring of original seals. Good sealing performance protects clutch friction components and cuts oil waste for heavy-duty long-haul transport vehicles.

Product Advantages Constructed from high-temperature resistant modified rubber compound, maintaining stable elasticity under sustained engine heat. Precision ground sealing lip follows crankshaft rotation smoothly without abnormal abrasion. Reinforced metal shell ensures firm press-fit inside the engine block. Each oil seal undergoes dynamic rotation tightness testing before shipment, accurate dimension matching and convenient for engine rear end maintenance work.

Applicable Models Fit for heavy commercial vehicles equipped with 15NNS6B530A power unit, widely used on highway freight trucks with rear crankshaft sealing structure.

Q1: Why should the crankshaft runout be checked before installing this rear main seal?
A1: Excessive runout creates uneven lip wear and leads to recurring oil leakage shortly after replacement.
Q2: Can high engine blow-by pressure overwhelm the sealing capacity of this oil seal?
A2: Yes, abnormal crankcase pressure will push oil past the lip even if the seal itself is new.
Q3: What tool type is recommended for pressing the seal to avoid lip damage?
A3: Use a dedicated seal driver with flat face to apply even pressure on the metal shell only.