bad door seals
your heater core is leaking
Look underneath the passenger seat, it should be in a bag mounted to the floorboard.
YES. Good possibility if it is leaking at the passenger side
most likely cause is your heater core leaking
Perhaps slave cylinder, line or fitting leaking?
It could be the coolant overflow tank that is leaking.
it should be under the hood on the passenger side on the firewall.
Broken line at the heater core possibly
Water pump removal chevy monte carlo 3.8
No
In the fuse panel on left side of dash can only be seen when passenger side door is open.
There is no such thing as a 2008 Monte Carlo, so the answer would be no.