Changing the alternator in your BMW doesn’t have to be an expensive trip to the repair shop. One of the biggest barriers to entry for owning a used BMW is the cost of repairs and service, which I admit, is too high for most people. If you love the driving dynamics of a BMW as much as I do, then rolling up your sleeves to do the service work yourself is a worth while tradeoff.
Generally speaking, once a used BMW reaches between 100-120k mile mark is when everything starts failing. This is especially true for cars that have been poorly maintained during that time, and maintenance has been deferred to the last possible moment. It’s very common to find used BMW’s for sale around this mileage because the owner realizes it makes more financial sense to pass the problems on to someone else. In my experience, this is the most common scenario unless you buy a used car from an enthusiast or in the rare case- the original owner took good care of the car.
I’ve uploaded a video guide on how to remove and install a new alternator in your M54 engine, which covers the E46, E39 and E53 X5 models. The plastic air box and space to work may vary between these models, but the engine and alternator procedure is essentially the same.
You can order a new alternator at a great price right here.