BMW 740Li xDrive Drive Belt Idler Pulley Replacement Cost

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

Drive Belt Idler Pulley Replacement
The average cost for a BMW 740Li xDrive drive belt idler pulley replacement is between $341 and $395. Labor costs are estimated between $202 and $256 while parts are priced at $139. 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 Idler Pulley Replacement

What is a drive belt idler pulley?

The term “Drive Belt” is a generic term used to describe a set of belts that are used to run engine accessories such as the alternator or power steering pump. These belts must be routed in a manner that prevents contact with other belts or components, necessitating the use of an idler pulley. This helps locate the belt, while allowing it to spin freely.

How does the drive belt idler pulley work?

While the engine is running, the crankshaft pulley is constantly spinning. This provides drive to other mechanisms by means of a belt. The belt will be tightly wrapped around the crankshaft pulley and the accessory pulley, so the belt is unable to slip. Manufacturers use idler pulleys to route the belt around various engine accessories.

What are the symptoms related to a bad drive belt idler pulley?

If the drive belt idler pulley fails, there will be a very audible chirping noise from the front of the engine. This is because the idler 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 slip off. If the belt falls off, the accessory that it drives will no longer function. For instance, if the alternator belt idler pulley fails, the alternator may stop functioning. Also if the pulley begins to wobble, allowing slack in the belt, it will make an extremely loud squeaking or screeching noise, especially on cold starts. This is the belt slipping on the crankshaft pulley, and will require belt replacement once the idler pulley is replaced.

Can I drive with a drive belt idler pulley problem?

Depending on which belt breaks, driving the car may be hazardous or impossible. The power steering belt and air conditioning compressor belt will not disable the vehicle, but the vehicle may be unpleasant to drive. If the engine cooling fan belt breaks the engine may overheat, causing further damage. If the alternator belt is broken or missing the vehicle will need to be towed, as battery power will only last a few short minutes.

How often do drive belt idler pulleys need to be replaced?

Idler pulleys tend to last quite some time. However, driving style and operating environment may affect part longevity. The majority of vehicles will surpass 100,000 miles before idler pulley replacement is needed.