Dan,

Yes, I also noticed that the engine type on JimF's website didn't match my question. So, going back to my first post, is this a rod knock I'm hearing and does it do any harm? Could that checkvalve be stuck open? Not being able to see a diagram of the oiling system, where does the oil from the pump go to first? I did hear two lifter clicks on first startup for the day yesterday which is the first time in 11000 miles. When my car finally goes in for the B service, Mobil 1 0W40 will be used, not the Mobil 1 15/50 I'm using now. Which won't change anything because that was the original oil (0W40)which was replaced at 4000 miles when the oil level sensor was changed and the thing was knocking previously.

Roger Ellingson/Seattle/Still the best MB I've owned out of six.