OEM Equivalent Numbers
8PK1390, drives the accessories, replace every 3-4 years or every 80,000 kms
Your BMW's accessories are driven by a rubber belt along with a system of pulleys and tensioners. This belt with age can stretch causing the belt to slip on the pulley system. Additionally, exposure to severe heating and cooling cycles can dry rot any drive belt causing the belt to crack and fray. We recommend replacing serpentine belts ever 3-4 years or every 80,000kms.
Accessory Drive Belt
An accessory drive belt, also referred to as a serpentine belt, functions by transferring power from the engine crankshaft to various accessories like the alternator, water pump, power steering pump, and air conditioning compressor. Essentially driving these rotating assembles through a series of pulleys with the belt's rotation. It is important to check the belt for cracks, fraying, or excessive wear during routine maintenance, keeping in mind most manufacturers recommend replacing the accessory drive belt at specified mileage intervals, typically between 80,000 and 100,000 kms. Proper tensioning of the belt is also crucial, so while servicing or inspecting an accessory drive belt, it is important to also inspect the belt tensioner and supporting idler pulleys.
Accessory Drive Belt Failure Symptoms
Wear and tear: Over time, the belt can become cracked, frayed, or glazed, causing it to slip on the pulleys.
Misalignment: If pulleys are not properly aligned, the belt can rub against them unevenly, causing wear and noise.
Tension issues: Incorrect belt tension can lead to slipping or excessive strain on the belt and its components.
Contamination: Engine oil, coolant, or debris can degrade the belt material
Excessive Noise: Squealing noise, especially when starting the engine