Hi, your problem is probably dealing with the thermostat which comes as a complete unit, i.e it lies in a sealed plastic holder costing about 25 quid. Had the same problem as you which got the cooling fan running most of the time. These symptoms disappeared as soon as i got the new thermostat fitted. The fitting can be a bit fiddly though. Good luck.
Mo
Its in housing where the bottom radiator hose connects.
It is an in line thermostat and is housed in a 'plastic ball' in the bottom radiator hose.
Look on top of the radiator and follow the hose from the radiator to the thermostat housing. Look on the bottom of the radiator and follow the hose up to bottom of the block.
The lower radiator hose is located at the bottom of the radiator.
Look on top of the radiator and follow the hose from the radiator to the thermostat housing. Look on the bottom of the radiator and follow the hose up to bottom of the block.
The bottom hose on a 1993 Altima is at the bottom of the radiator on the passenger side of the car(right side of radiator.
lower radiator hose
Remove the bottom radiator hose. Put a garden hose into the top of the radiator. Allow the garden hose to run until the water coming out of the bottom of the radiator is clear.
Upper is hose connected to top of radiator, lower is hose connected to bottom of radiator.
The thermostat connects to the top radiator hose on a 1996 Toyota Corolla. The bottom radiator hose connects to the water pump.
The thermostat has not opened yet.
Remove the bottom radiator hose. Stick a hose in the top of the radiator. Turn the water on. Allow the water to run through the radiator and out the bottom of the radiator.