They don't need to pull the motor, they just drop the tranny. Clutches aren't too expensive for older cars. To flush the radiator just climb under it and look for a plug in the radiator, put a DEEP pan under it and take the plug out, when the motor is cold of course and take the radiator cap out of the top of the radiator and throw it away. When all the fluid is drained out flush it with fresh water until you feel safe about it. Put the plug back in the bottom and full it up, putting a new radiator cap on.