overheating problem.

my car started to overheat today according to the guage. there was no steam from the bonnet though. after checking there was plenty of water.
i have just tested my fan coupling with a rolled up newspaper.
the fan stopped easily when cold but even when the temp went above the half way mark the fan still stopped easily.

I REPLACED THE FAN COUPLING
AT THE SAME TIME I REPLACED THE THERMOSTAT

still have the problem.

well now i have taken out the water pump. it looks fine. no damage at all.
could this still be a problem or would there be signs.??????

please help as this is getting to be very exspensive and time consuming and i really need the car back on the road.
any help or advise would be appreciated.

By fan coupling I assume you mean the clutch (the aluminum finned casting that attaches to the fan blade). After replacing all parts did you bleed the coolant (some of these machines require bleeding after opening the cooling system). Warm car up to normal temp and then open the bleed screw (on the thermostat housing) until coolant start to flow, and let coolant slowly flow out until no bubbles are seen (may take a couple of trys).