I'm a total newbie with the oil and filter scene, this site was recommended to me by a friend. So I'm still learning and I've been searching the forum for the last week. My car's engine has 195,000 miles (car's mileage is 169,000) and is decent shape. I've changed all the gaskets, the engine has a new head since 189,000 miles and compression is at 170 (dry) with stock compression specs of 162. So I assume the walls and rings (at least compression) are in decent shape. I am thinking (and hoping) that I might have sticky rings, after reading about the Saturn members. So I am also going to try Auto-RX. Another important factor about the engine is that I've had the car's engine since 175,000 miles and it sat for a full year w/o use. It was "winterized" (used flogger) for that time. When I started the engine after its hibernation, I made sure it was primed, again with Texaco 10w-30 and a primed puralator PureOne filter. Since I've owned the engine, I've used Texaco oil 10w-30 exclusively, until recently (3mo/3k changes). I switched to Valvoline 10w-40 maxlife, in hope to reduce oil comsumption. These days it uses about 1qt/1000 miles. And that is with the maxlife. Prior to MAxlife use, the car would burn a lot of oil under acceleration when the engine is cold. That aspect of oil use has gone down considerably. This is most likely because of the 10w-40 weight and recent climate change (got colder). Since valvoline's reputation isn't as good as I had thought, I've bought a case of Castrol GTX 10w-30. I intend to use this with Auto-RX. Here are the questions... 1) I've read here 5w-30 or 10w-40 weight isn't fantastic...if the auto-rx doesn't clear up my oil problem, would 20w-50 be a better choice? 2) Is it a bad idea to use 10w-30 with the auto-rx application? Should I stick to 10w-40? 3) Should I change to Synthetic after the auto-rx application? I'm not worried about oil leakage, as all gaskets are fresh as of 189,000 miles. Would there be a benefit? If I change to synthetic I'll use Amsoil, as I can get it locally. 4) Also my car's owners manual only recommends two oil viscosities. 5w-30 from 32F and colder, 10W-30 -10F and warmer. Would 10w-40 or 20w-50 increase wear? 5) Recommended oil change intervals? Thanks for your time, its a length post.