Has anyone tried the Lucas oil additive for the 5w-20 oils it's supposed to quiet up the valvetrain a little when the car is cold...or maybe run a little heavier oil like a 10w-30.

 

Boy why would you want to do that? DC is very specific about the kind of oil to use, if you try to put something in it to make it heavier you risk issues with the valve train and esp. with the MDS. Just stick with the 5w/20 like the book says.

Oh and I have no valve train noise to speak of..