Motor runs but does not heat food

I'd say don't play with your microwave. These things can cause you a nasty injury or death if you don't put them back together correctly.

Service technicians have a tool to measure leaking microwave levels after the put them back together.

Your best choice is to get it professionally repaired if it is an expensive model or just get rid of it and buy a new one.

I don't suppose it is still under warenty.