I changed the oil on my 95 s420 and the oil pressure isn't registering. I'm scared to start the car up. Why could this be? I followed the directions in the D.I.Y. section. I had a small metal ring in the package along wth the filter and the seals. I didnt know what to do with that. I still have it. Could that be the problem? I drained and added the oil with the front end proped up on ramps. Could I have done something wrong? Please help I need to get to work in the morning!