2010 kenworth t660 low coolant warning

[Bigstank]

I got it from MHC kenworth in Springfield mo. That's where im from. Yes they told me it just pushes up and snaps in the bottom. I changed it out and the new plug but it just comes on and off when she wants and that dinging drives me crazy lol. Kenworth told me it possibly cold be the float in the coolant tank but I don't wanna spend $300 to change a tank that's not cracked, broke or leaking.