well, it doesn't get super hot or whatever. just whenever i blast the a/c for a while, it'll flash red. i turn a/c off and it goes away. do i need to replace the thermostat or do a radiator flush? seems like the radiator fluid does need to be replaced. no knocks or weird noises. it's a great car and want it to last me through 4-5 more years so i just want it fixed. thanks!