Another important function of the oil seal is to keep contaminants out of the engine. Dirt and debris can enter the engine through various pathways, including the air intake and exhaust systems Dirt and debris can enter the engine through various pathways, including the air intake and exhaust systems Dirt and debris can enter the engine through various pathways, including the air intake and exhaust systems Dirt and debris can enter the engine through various pathways, including the air intake and exhaust systemswheel oil seal. If these contaminants reach the oil seal, they can cause damage and reduce its effectiveness. To prevent this, the oil seal is designed to be resistant to these contaminants, ensuring that the engine remains clean and free from damage.