I am about to replace a water pump on my 1990 300E. I would appreciate procedure for pump replacement. If nothing else, information on serpentine belt tensioner adjustment. How is the belt properly removed and then adjusted on replacement? Does the tensioner mechanism have to be removed to replace the water pump? It looks like it would be easier if I remove the radiator...agree? Any special tools required before I start? I have a 1988E, 1990SE, and 1992E. I could probably benefit from a repair manual. Any idea where to find one. Many thanks, in advance, for any help you might be able to give me.