i have a 2002 oldsmobile intrigue and i just had the water pump changed out and the alternator , brakes, and spark plugs and wires changed and even an oil change the engine is a 3.5 liter and my car is running hot ive had the thermostat checked and the guy told me that that wasnt the problem although second opinions do count there are no obvious leaks but everyday water is neded in the resivior what could be my problem?