Hey Steve,
If you've never replaced the fan clutch on a W124.133 (or .193), it's NOT easy. If you don't have the two special tools I **highly** recommend pulling the radiator. This will also allow you to clean the radiator fins, and condensor fins, thoroughly while it's out. Also a good time to inspect the serp drive belt and tensioner (tends to fail every 50-100kmi - must be perfectly parallel, if angled at all, replace ASAP). Clean up the face of the clutch & flat bimetal spring before installing. DO NOT remove, bend, deform, or otherwise mess with the flat diamond-shaped spring, you will ruin the clutch!!!
With the special tools you can R&R the clutch in 5 minutes with the rad installed, without the tools plan on 30-60 minutes, lots of French, and skinned knuckles. They tools needed are:
Short, stubby 8mm hex socket tool (3/8 drive) - cheap, ~$5-10 from dealer??
Spinner tool to spin the bolt out (hard to describe - I should take a picture of the one I made for ~$5, instead of spending $50-75 for the MB tool)
Serp belt holding tool so you can torque the bolt on & off (NOT cheap - $50-$90)
If you're interested I might be able to take photos, and/or get part numbers.
Have fun!
