[custom10nut]

Could it be as simple as needing to add a higher concentration of coolant?
I seem to recall that the issue started after my son (with good intention) flushed the coolant system.
I’m going to go get a new sending unit and replace the coolant to see if that fixes it.
On other thing I’m going to look at is my timing. It may be a little too advanced.
I’ll let y’all know how it turns out