If the 8th digit in each car's VIN is the same, then yes.
A 2000 Buick uses Dexcool.
5 QUARTS
PFM
Can 24 inch rims fit on a Buick le sabre 2000
Instructions for replacing radiator on 2000 Buick Lesabre custom
The best place to start is by figuring out what's wrong with it.
Normally 180 On hot days it might go to 200
17.43535537 gallons go here for info: http://www.internetautoguide.com/car-specifications/99-int/2000/buick/century/custom-sedan/526/index.html
A 2000 Lesabre is not designed for E85. While the car might operate on E85 the fuel system is not built for it.
The oil filter is located near the serpentine belt and is reached from below the car.
you will need a fuel pressure and flow gauge and then check actual meaured to specs.
You may need a new flasher.