It was indeed a very involved DIY project. I spent a good eight hours R&R the darn thing on my 1989 190E 2.6. Ended up buying a 13mm swivel quarter drive socket and a 4 inch flexible extension at Sears to aid in getting at that forward lower mount bolt. A third of that eight hours I spent was trying to get to that one bolt.
I was having intermittent temperature rise indication, not quite overheat; then I placed a blade end of a screwdriver to the water pump and listen with my ear on the handle end, lo and behold, the chattering noise was very audible.
Although much laborious hours were spent, the cash I saved from having it done at a shop made every effort worthwhile.