I bought a mint 2003 Mercedes S500 a month ago with a loud "ticking" noise. I bought it at a salvage price because of the noise. It has 130,000 miles. I took it to my 30+ year
experienced MB mechanic. He said he has checked the car throughly, and the noise has to be a lifter. It idles perfectly & drives likewise. He said the engine inside was one of the
cleanest he has seen. He wants me to drive the car on a long trip with Marvel Mystery Oil. He feels it stop the noise. My question is why would there be lifter noise with the engine
being so clean? Also, any recommended oil additives that have proven to work? Any insights
appreciated!

Richard