My 740GLE overheats badly when idling in hot weather but OK when\nmoving moderately fast. Except for the idle speed that is rather\nerratic (some day exactly where it should be around 750 rmp, other\ndays at 500 or 900 or switching to different speeds in between) there\nis no other problem. Of the few items I have to check to fix this\noverheating the thermal fan clutch seems to be the hardest. When the\ncar is cold there is a resistance when I try to turn it by hand (it\nwon't spin.) This morning when I got to work (after some 30 km drive)\nit seems to offer the same resistance when I tried to spin it. Is this\nindicative of a faulty fan clutch? Not knowing how stiff a hot fan\nshould be I have no clue as to whether the fan clutch is good or bad.\nCan somebody tell me if it should offer subtantially more resistance\nonce the car has reached normal temperature or does this "more\nresistance" only occurs when the car is over the normal temperature\nrange and only when hot air is blowing past it. I will do this "cover\nit with a blanket test" later if this is considered inconclusive.