Thanks for you reply guys.
I was thinking to replace the belt driven fan with an electric one.
The auxiliary fan is wired to always run when the AC is on.
The engine gets hot when driving uphill and in city traffic.
It's actually a 88 560SEL with a 617A motor.
The engine is almost new and the radiator and oil cooler cam out of a
81 300 SD.
I use a 75 dec.C thermostat and the fan clutch seems to work ok.

What about the special coolant that promise to keep your engine running
10 dec. cooler.
dose that stuff work?

Thanks
Tom