Ok, been reading alot of threads about people using Royal Purple motor oil to quite the piston slap. So i decided to try it and i changed the oil last night in my 2002 4.8L. And on a cold start this morning at about 30*, the noise caused by piston slap was greatly reduced! Both by length that it occurs and how loud it is. So i guess that is a good thing, but still hate that we have to fumble around with different types of motor oil to reduce the noise made by a design flub!

I wouldn' go to extremes to try and get oil to correct this, many thousands or more of GM and Ford engines have 200k with piston slap cold and have had no issues.

Im not going to extremes it doesnt bother me that much, but the more little things i can do to make it less noticable im going to try it, plus the royal purple isnt that much different than paying for any other leading synthetic oil. So if it helps....... Why not?

I have 3 regulars at my shop w/ ver 200k. Still run and look good, two are 99-02 type and a ~03 4x4. How much did the royal purple run you?

I had to order it through summit cause noone local carried it. It was around $7 a quart, which is what you pay at the stores for some other synthetics.