Why does engine temperature drop to almost cold when I go down hill?
My car was overheating, and thank God I caught that and made it to the mechanic. He switched the thermostat, but the radiator still wasn't heating up. He tried putting a hole in the t-stat, didn't help.(Could it have?) it turns out the water pump was totally dead (the "teeth" fell out!), and he switched it out. Now the engine takes a good while to warm up, and if I go down hill... the engine actually cools down.. to 1/8 the gauge, instead of staying right in the middle. Did the mechanic ruin the t-stat? Is it stuck in open? The only way to prove this to him is to have him drive up a big hill with me... the temp gauge stays in the middle when its idling by the time I get to the mechanic's. Any advice? Thanks!