Alright I need help! I’ve got a 2018 equinox that I’m now having significant cooling issues with. It had started off with a water pump that needed to be replaced. (Fins were damaged) as well I replaced the thermostat just to be safe. About 2 months later the car started to overheat again after about an hour of driving. Took it to mechanic and he said he flushed the heater core and it looked fine. Still overheating so i decided to take a look at the thermostat again. It turned out to be faulty and wasn’t opening all the time. Replaced it with a new one that I verified was working. After that was done I put everything back together. But now after about 10 mins of driving the temperature with spike and then go down. I am absolutely confused on what’s going on. Any ideas would be greatly appreciated