The crankshaft seal is located in the crankshaft of your vehicle. The crankshaft converts rotary into linear motion. This means it uses the force created by the pistons in the engine to move in a circular motion so the vehicle’s wheels can turn. The crankshaft is housed in the crankcase, which is the largest cavity in the engine block. For the crankshaft to work properly, it must be completely lubricated with oil so it is free of friction. There are two crankshaft seals, one in the front and one in the back, which are known as the front main and rear main seals respectively.
Since the crankshaft needs to be lubricated, there are seals on both ends of the crankshaft that keep the oil from escaping. In addition, the seals help to prevent debris and contaminants from entering the crankshaft itself. If this happens, the crankshaft may become damaged or stop working.
The crankshaft seals are made from durable materials so they can stand up to the harsh environment of the crankshaft. The materials they are made out of may include silicon or rubber. Although they are designed to handle the high pressure and temperatures, they can become worn and damaged over time.
The front seal on the crankshaft can be found behind the main pulley. If the seal starts leaking, the oil will get onto the pulley and oil will get thrown onto the belts, steering pump, alternator, and anything else that is close to the area. The rear seal is located along the transmission. The process to replace a rear crankshaft seal is complicated so it is best left to a professional mechanic.
Since the crankshaft seal can go bad over time, it is a good idea for you to know the symptoms before it completely fails.
Signs your crankshaft seal needs to be replaced include:
- Engine oil leak or oil splattered on your engine
- Oil spraying on the clutch
- The clutch slipping because oil is spraying on the clutch
- Oil leaking from the front crank pulley
The seal is an important part to keeping your crankshaft running smooth, and your crankshaft is necessary for your engine to run properly. Therefore, this repair should not be delayed.
This article originally appeared on YourMechanic.com as How Long Does a Crankshaft Seal Last? and was authored by Valerie Johnston.