so i picked up the car last saturday from the mechanic. he did a tune up replaced all belts, a few hoses. on the way home i noticed the temp light was on.. its not bright so i didnt noticed when it first turned on. it took me about another 45 minutes to get home and i got there no problems. everything seemed fine... then i took it out again last night light turned on right away. same thing drove it for about 2 hours nothing happened runs good no problems. i ordered a new coolant bottle and cap cuz it seems to not make a tight seal. also replacing thermostat this weekend.. any ideas why temp light is turning on??