Hello my name is Ken. I recently had a Iridium Silver 2005 Slk 350 manual in which I had since 2005. Recently I had to say goodbye to her as I was struck from behind and thrown into a guard rail spinning, six times! Needless to say she was totaled, but I want everyone to know that I am fine and the car amazingly still started and drove, doors still opened fine and amazingly the roof still retracted! Any ways I recently purchased a 2009 SLK 55 AMG and wow what night and day difference! The color I always wanted and all the power! So I performed its first oil change by me since I work on vehicles for a living and now are in my twentieth year in doing so. Now I bought it with low miles and I don't know what the previous owner used, but I used Mobil One 0W40 full syn European formula and added 20% Lucas oil stabilizer to it. Now I drained both drains and the oil cooler and of course used a factory Mercedes oil filter. My issue is now there is a whine present on start up but seems to go away after its reved a little. I have read where people think this is the oil pump. The noise does seem to come from the oil pan. I used Lucas always in the Slk 350, but are the 5.5l amg motors to sensitive for Lucas oil stabilizer? Thank you in advance for your replies.