I have a 90 420sel with 110k miles. My MB mechanic has said to redo the timing chain between 125k & 150k. I am terrified that before I can have done (in about 2-3 weeks) I will have a disaster with mega bucks to rebuild the motor. Can anyone tell me the symptoms of a worn out timing chain, like the noises heard or the way the car drives, idles, etc. Any details you can give would be greatly appreciated. Thanks. Scott