1985 Mercedes Benz 380se

Engine Cooling problem
1985 Mercedes Benz 380se V8 Two Wheel Drive Automatic 220000 miles

Hi, I have replaced the water pump and thermostta 3 months ago. Bearing shot, now all good. 2 weeks ago car developed overheating problem. When stationery in trafiic temp runs up to 110c, when on highway still running hot at 105 c. I have removed thermostat thinking may be flow blockage, but no difference. New fan belt on and firm. I have put a 2nd hand clutch fan on. Seems to have much stronger air flow when idling. When I rev the engine the fan locks in and drives plenty of air then cuts back out again after 2 or 3 sec when car is stationary. How do I know if the 2nd hand clutch fan is working to specification? Should the fan lock in and stay locked in or fall back to freewheeling when I rev the car in stationay position ? I am trying to understand the charatceristics of these fan clutches. New ones are very expensive like $1000. I have flushed the water system and run descaling thru it. Overheating problem still here. Ta bruce
February 24, 2009.

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