Oil level warning lite and annunicator lite

The oil level warning chime and dash annunicator gives a warning indication approx every 5 minutes. I have checked the oil level numerirous times.(Using the dipstick) The level is at the exact level that it should be. Oil and filter were changed and refilled to the proper level. The problem still presists I have spoken to the Mercedes service techs (via phone) and they say; the problem is that the oil level sensor needs to be replaced. "Bring it in and have it checked" The estimates are north of $500 He also stated that the oil pan itself will have to be replaced because it will be warped. (Along with a seal) Sounds funny to me that the oil pan would have to be replaced. I have worked on cars for many years so with the proper instructions I feel I will be able to do the job myself What I need are instructions and scametics and or pictures.