so i notice some odd noises coming from my car, swear under my breath a couple of times and keep driving. about 10 minutes later at a stop light i notice my temp. is up to about 245-250. HOLY SH!T so i start to drive and it instantly cools down to about 215-220ish. long story short it stayed pretty much between 210 and 250 between stop and go, 30mph, and 70 mph on the highway. and it would flucuate like crazy. i can look at it for literally no more than 10 seconds and it would go from 210 to 250 or viseversa. now for about the last week my low coolant light has been coming on but didnt when i noticed this happening. so obviously time for a coolant flush/top off but is it possible a sensor is bad or i have more issues beyond just these?