This engine works with the Hill Climb Racing Microsoft Store version.

"Processes -} HillClimbRacing.exe"

Then simply double-click on the value box and enter your desired amount.
I did it like this : 99,999,999 coins - 99,999 diamonds
But don't overdo it, otherwise you will slip into the red, should that happen just enter a "0" again and try again.

Author: xxRattenKlatscherxx