Coolant level

What.

When coolant gets hot, it expands.

I’d probably put a bit in it, as i don’t like mine below anything.
Just keep eye on it, if it’s something new going on.

 

What he said ^^^. And you are kind of thinking backwards. If your coolant level rises you definitely don't have a leak.

My Volvo does this too. Especially after opened the cooling system for any reason, like when a hose blew recently. It takes a few days of cycling the engine to get the level back perfect. You're shooting for the surge tank (overflow tank on top of the motor) to be at the top line etched in the plastic when it's cold. Don't worry about where it goes when it's hot, unless it goes way down.

Your truck is smart though, meaning lots of sensors. If coolant gets low it will tell you on the dash and you won't miss it, trust me!