[s-cars] strange noise in S4

[john cummings]

	My wife drove our  94 S4 to work this week. After 4 days she said " by 
the way its making a funny noise but it is driving ok".
	The noise seems to be  coming from the front  behind the radiator. No 
leaks, overheating, charging problems, or oil pressure issues. Does not 
sound like metal grinding or squealing more like a rhythmic vibration 
of something against plastic or light metal.  The fan comes on high as 
soon as the car starts up. There are no fuses to pull or metal link 
like in the 20v 200.......  so what is the quickest and easiest way to 
eliminate the fan as the source of the noise? Don't want to run the car 
for any length of time for fear its something like a timing belt 
hanging on by a thread.   Hoping that is not the case...... TB was 
changed about 60K ago.
	 In the past I have had the tendency to waste a lot of time in futile 
attempts at problem solving while a really obvious solution was staring 
me right in the face.

TIA for any suggestions
John Cummings

PS I have read many posts in the past praising the simplicity of these 
older Audi engines in comparison to the New Audi stuff. To me this  
engine seems  to be a complex maze of sensors and wires compared to the 
tractor like 60's era Volvo engines I have the most experience working 
on.