Honestly...it really doesn't make too much of a difference what viscosity you choose, as long as it's not 4 levels of viscosity out of the mfr's recommended fluid or something silly like that.

Changing your oil type might help quiet down a valve train a little bit, or for a temporary period, but it's a band-aid, and it probably won't fix your valve train if the noise is being caused by parts with excessive mechanical wear. In other words...just replace your lifters if you want the ticking to go away. Double check it's not low oil pressure causing the sound, though.

If you're in a warm climate like I am, you can virtually ignore the "W" rating on your oil, as it probably doesn't get cold enough to operate at that viscosity (unless I stay overnight in the local mountains in the winter, and a small handful of rare, cold nights elsewhere per year).

I've tried every oil under the sun, in some pretty high powered, high-boost applications. For me, I pretty much stick to Royal Purple in the trans and Mobil-1 in the crank case. I can't think of a vehicle I've owned that's run anything other than a 30 or 40 weight oil. From 1.8L SOHC 4 cyls, to 2.3 DOHC 5 cyls, to 2.8 and 3.5 DOHC 6 cyls, and 5.0L SOHC 8 cyls...some supercharged, some turbocharged, some N/A...some DD, some tracked...it's always been a 30 or a 40 weight of some variety.

Don't worry too much about it...in the end, I doubt it makes more than a few thousand miles of difference on a 200k mile motor...as long as it's well maintained and kept clean.

<img src="/forums/images/graemlins/cheers.gif" alt="" />