when its cold it should spin along the engine, but not along the rpm. as it gets hotter, it locks up and spins along with engine rpm. when u will rev up u will see and hear it spining along the rpm.Originally Posted by BMW
you should be able to stop it with ur fingers when car is cold and ticking over. u will be able to stop it even its locked but u will feel that.
take of the radiator cap, how is the water flow? it should be sligtly flowing even when idleing. termostat- if it keeps steady above 90c when driving and in trafic, its defo not gonna be termostat. if termostat stck open, on higher speed u will have the temp down if stuck close in trafic it would overheat.
i would take the radiator of and give it a good flush.
ps remember, botom hose will always be colder than top hose, as the coolant from radiator is going in, to cool the engine, and the colant from top hose is coming out of engine.
pps m44 engines has termostat with 95c opening temp