Seals (Hydrodynamic)

The hydrodynamic seal is different from the lip-type seal. The difference is the hydrodynamic grooves in the sealing lip of this seal. These grooves move lubrication oil back into the engine crankcase as the crankshaft turns. Because of this seal lip design, the front seal for an engine is different from the rear seal. The installed position of the seal lip is important because the seal grooves are sensitive to the direction of crankshaft rotation. Each seal is marked with an arrow to show the direction of engine rotation. If the seal is not installed correctly, oil in the crankcase will actually be removed. Special handling and installation procedures are given in Special Instruction, Form No. SMHS8508