Modern BMWs in general need service at 30K intervals with oil changes in between. The first one is usually at or about 30K miles as determined by you car and how it was driven, and is known as Inspection 1. Inspection 1 is usually covered under warranty, but is basic enough for the shade tree mechanic to complete. At 60k at or about comes Inspection 2, which is more complete, and is outside of the warranty period, and usually some steps are outside the DIYers comfort zone.

Inspection 2 can be carried out by an independent BMW shop rather than the dealer and can save you quite a bit of money.

This is not to say however that your X5 may need work such as brakes or coolant between inspections 1 and 2, and the inspections are not a substitute for good maintenance.

In your case though, I suspect that since the extension being offered to you does not cover Inspection 2 that it is merely a ploy to separate you from 10 $100 bills, however, if it covers brakes and coolant, and you think you might need these items (inspect your brakes, and coolant should be changed every 4 years, every 2 even better) it may be money well spent if you are unable to do it yourself.

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BMWCCA Chapter President, Hawaii Chapter (fmr)
03' X5 4.4i, 02' MCoupe, 99' MCoupe (sold), 88' M3, 01' E39 M5