My son in law has a 01 mustang v6 3,8 the engine light came on and the code is p1285 i just replace the thermostat my water pump is working the temp is staying is the same place where it belongs but it is still giving me that cold i am not using any antifreeze can any one help with this plz
If it's not overheating, it could just be the temp sensor failing you.
Front end of the lower intake in the coolant passage.
Also, just a suggestion - run a 50/50 coolant/water mix. Straight water will eat up the water pump, rust out the heater core and destroy the head gasket at the coolant port between the lower intake and the heads.