Many miles ago, the service tech failed to reattach the mechanical fan after replacing the alternator and I didn't notice it for over a month until I smelled anti-freeze one evening. I took it back to the dealer and my service writer unloaded on the tech like a freight train. A week after the mechanical fan was remounted, the expansion tank blew (that's probably where my telltale odor was from) and the dealer picked up the tab on that. Then as we entered springtime temps a few weeks later, I realized I had no A/C at idle. The dealer determined the aux fan had burned up too - probably because it was handling the engine cooling load as well as the A/C. So, I wouldn't chance using just the standard aux fan as the sole cooling source. The single fan from the N62 engine is probably a more severe duty unit.

2002 X5 3.0 340,700 miles
2014 428i 36,900 miles

2004 325i Sold at 123,600 miles
2001 325i Sold at 66,000 miles

1970 Firebird Under Restoration