I took her out of storage last night for a little whip around the neighborhood and decided to test out the 10w30 oil and what it would do to my "marble in a can noise". I used exactly 6 qts of motorcraft 10w30 (1/2 qt in filter, 5 1/2 in engine) with the motorcraft 820s filter. Started her up and the noise was there but I will say after driving for 20 miles she was quietiest shes ever been. At idle she purred beautiful with no rattle. I drove her to work today and will see how she sounds stone cold because that is when the rattle is the most predominant. If it is not completely gone, I will not give up hope and keep my ear open for several 100 miles and if its still there it will documented with my dealer. I will stick with the 10w30 from now on though because overall my L just seemed to sound so much better.

On another note, if you are buying motorcraft oil, make sure you get the oil in the red bottle. The black bottle which Autozone is selling is older and has a lower API service rating.

Black Bottle- SJ
Red Bottle-SL

 

Rhino Slug, I have the rattle as well. I have got 9000 miles on the clock. I picked up some Mobile 1 synthetic 5/30 weight. Iwill see what happens. It still is driving me crazy. To what is going on. I will say if I drive it for some time and it gets warmed up some times I cant here anything. I still think it is piston slap. Thanks for the up date. Bob.

 

I put Mobil 1 5w30 in at the first oil cange and have never heard this problem in my 01. I have a little over 23,000 miles on it now. Added Mobil 1 5w30 in my 96 Cobra on the first oil change and never had any problems out of it either, and it now has about 155,000 miles on it.

Roger