i have both, 4.6iS and 4.8iS - the 4.6 has a single electric fan in front of the radiator, and engine driven fan on the other side of the radiator.

the 4.8iS does not have the electric fan in front of the radiator, it is moved to the back of the radiator...

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E53 X5 4.6iS
147K mi - Sold May 2013
Tireprints left in:
USA, Nicaragua, Costa Rica, Panama, Russia

E53 X5 4.8iS built 2005-10-17
66200 mi - June 2012
96000 mi - June 2013
112000 mi - June 2014
OEM fire extinguisher
OE first aid kit
OE tow hitch
OE TV module
OE aspheric mirror
K&N air filter
black/white badges
rear camera
4-channel video recorder

Here is the list of things I have done to the X