Question: How much does it cost to service a bmw 325xi and change the belts Answer: If you take it to a dealer, it may cost you $90.00 for oil change and $130.00 for the belt. A local shop will be what ever there going price is for oil changes, My shop charges $24.95 for an oil change that includes topping off fluid levels and $65.00 for the belt. My shop does not charge for shop supplies or disposal fees. Some shops do. Average is $35.00 for oil and $70.00 for belt.