95 420E runs hot

Check your coolant level first.

Then wash the radiator inside out... from engine outward to front of the car.

To check the fan clutch, engine must be hot... and it will pull alot of hot air toward the engine...

Was your AC on? If yes, did the aux fan come on? If not, then check the fuse for it... both in the fuse box... and inner deeper of the fuse box for the fan relays which also has fuses on it.

If it's OK at speed the radiator is probably working as it should be. Some cars' electric fans should operate when the engine or a/c temp passes a threshold. Suggest you investigate that the aux. electric fans are operating as they ought to before tearing into anything.