Is a 1999 olds 88engine compatible with a 1997 buick lesabre?

I have a 1997 Buick Lesabre custom that is having engine issues, i went to my mechanic he confirmed it would need a new engine soon. I dont wanna pay $2000 for it since i paid$1500 for the car and i was wondering if someone knew if i could replace my engine with the 3.8L V6 from a 1999 oldsmobile 88? and If it would fit like the other.Is a 1999 olds 88engine compatible with a 1997 buick lesabre?Yes they will work they are the same engine.