It is possible for the replaced thermostat to be faulty and without removing it for testing, we would not know.
You mentioned the low coolant warning indicator turning on and requires rerplenishment, that indicates the coolant level is indeed low. That could be due to air trapped in system and when the air has been purged to the reservoir, the level would drop.
Try bleeding the system to see if it helps.
Turn heater to maximum and let engine run for a few minutes to purge whatever air there is in system.
If turning on the heater helps to lower the coolant temperature, we can safely say the the water pump is good and pissobly the thermostat is not opening or there are som other clogging in system.
There are no standard procedures for performing test on water pump and the common practice is to remove the thermostat and run the engine while noting the coolant flow.
Tuesday, August 24th, 2010 AT 6:50 AM