Hey Mark, Mark here with a definite probably. My background - 45 years as an import tech with the last 10 being heavily German and euro stuff. Pretty sure I've put a radiator or condenser in a Sprinter but they all blend together. First up, the fan and/or clutch assy. is often removed in any front of engine work, if for no other reason then space or convenience. 2, would be really unusual for bolts that had been tight for 90K plus to ALL come loose. 3, seen it happen many times that bolts/nuts are started finger tight and then need to be finally brought to full tightness (these kind of fasteners are rarely torqued with a torque wrench due to access issues). One way to get an idea on some of this would be to get access to an on-line repair manual and see what it says, might even find this in a you tube video. I have a couple friends with sprinter vans, when I get a chance I'll look but this could take several days. Much more to possibly say about this.
Good luck, Mark D