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BMW 428i Gran Coupe Drive Belt Tensioner Replacement Cost

Know what price you should pay to get your vehicle fixed.

Drive Belt Tensioner Replacement
The average cost for a BMW 428i Gran Coupe drive belt tensioner replacement is between $221 and $238. Labor costs are estimated between $61 and $78 while parts are priced at $160. Estimate does not include taxes and fees.
Note about price: The cost of this service or repair can vary by location, your vehicle's make and model, and even your engine type. Related repairs may also be needed. Talk with a RepairPal Certified shop to learn which repairs might be right for you.
Drive Belt Tensioner Replacement

What is a drive belt tensioner?

The serpentine belt tensioner, or drive belt tensioner, provides tension to the drive belts to ensure the belts stay in contact with the crankshaft pulley and the pulley that belt is meant to drive.

How does the drive belt tensioner work?

As drive belts are installed the belt tensioner is tightened to manufacturer's specifications, placing the proper amount of tension on the belt. It is bolted to the front of the engine, and the flat side of the drive or serpentine belt rests tightly against the belt tensioner pulley. When the belt is driven, the belt tensioner pulley constantly rotates, keeping tension on the belt.

What are the symptoms related to a bad drive belt tensioner?

If the drive belt tensioner fails, there will be a very audible chirping, grinding, or rattling noise from the front of the engine. This is because the tensioner pulley bearing is no longer smooth, and rotating causes metal to grind at high speeds. If it is not changed immediately, there is a chance it will become dislodged, or allow the drive belt to lose tension, or break. If the belt falls off, the accessory that it drives will no longer function. Also, if the tensioner spring fails, allowing slack in the belt, it may make an extremely loud squeaking or screeching noise combined with a rattle as the tensioner bounces back and forth under load. The squealing noise is the belt slipping on the crankshaft pulley, and will require belt replacement once the belt tensioner is replaced.

Can I drive with a drive belt tensioner problem?

If the belt tensioner is totally destroyed, driving may be hazardous, or impossible. If the tensioner has just begun to chirp or rattle, the vehicle can usually be driven to a repair facility. Keep in mind that once the tensioner fails, the vehicle may only last a few short minutes before the engine stalls due to loss of electrical power from the alternator.

How often do drive belt tensioners need to be replaced?

Drive belt tensioner pulleys are only replaced due to suspected failure. They are not considered a wear and tear item, and are generally intended to last the life of the vehicle. However, the majority of vehicles will see a drive belt tensioner replaced before the 125,000 mile mark has been reached, with some replacements occurring as early as 50,000 miles.