Genuine BMW Front Main Seal, BMW B48

The front main seal, also known as the front crankshaft seal, plays a critical role in the proper functioning of an engine. 

BMW Part Number: 11118664905

Purpose

1. Prevents Oil Leaks: The primary function of the front main seal is to prevent engine oil from leaking out of the front end of the crankshaft. It seals the gap between the crankshaft and the timing cover or the engine block, ensuring that the oil stays within the engine.

2. Maintains Oil Pressure: By preventing oil leaks, the front main seal helps maintain proper oil pressure within the engine. This is crucial for the lubrication of internal engine components, which reduces friction and wear, and ensures smooth engine operation.

3. Protects the Crankshaft and Bearings: The seal keeps dirt, debris, and other contaminants out of the engine, protecting the crankshaft and its bearings from potential damage. This helps in maintaining the longevity and reliability of the engine.

Location and Function

- Location: The front main seal is typically located at the front of the engine, where the crankshaft extends out to connect with the harmonic balancer, timing gear, or pulley.
- Function: The seal fits tightly around the crankshaft and within the engine housing, creating a barrier that prevents oil from seeping out and contaminants from entering. It is designed to handle the rotational motion of the crankshaft while maintaining a tight seal.

Symptoms of a Failing Front Main Seal

- Oil Leaks: Visible oil leaks at the front of the engine, especially around the crankshaft area.
- Low Oil Levels: Frequent need to add oil due to unexplained oil loss.
- Oil Spray: Oil may be sprayed around the engine bay, particularly near the crankshaft pulley.
- Unusual Noises: Unusual noises from the front of the engine, possibly indicating that the seal is worn and not functioning correctly.

Maintaining the integrity of the front main seal is essential for the health and performance of an engine. Regular inspections and timely replacements, when necessary, help ensure that the engine operates efficiently and reliably.