ford now recomends using 5w 30 in most engines originally built for 10w30, going back to the late 80's.

 

Might want to check out www.bobistheoilguy.com.

Interesting info about Lucas at that site.

 

I saw that sight-but its not swaying me its not scientific enough to prove airation in the oil

 

If you guys wanna keep this thread going, please stop bumping the language filter and talking like a bunch of 8 year olds. Otherwise I'm going to close it and begin handing out warnings, activating the "3 strikes you're out" rule.

 

Wow! A chemistry thread and I'm a chemist.....how fortuitous.
I also spent the first 5 years of my professional life as a formulator of lubricants. Motor oil and gear oil both may contain sulfur and phosphorus.
A common EP (extreme Pressure) additive used in motor oil is zinc dialkyldithiophosphate. It has both sulfur and phosphorus in it. BTW, most oil has SOME sulfur in it naturally. It's refined out to make cleaner-burning gasoline. In fact, crude oil from differing areas has differing native sulfur content, but I digress.
Gear lubes typically use higher amounts of sulfur-containing additives, such as molybdenum disulfide, but newer compounds that are less corrosive, are also used in higher priced lubes. For a good general description on some of the better additives, I recommend reading:
http://www.rtvanderbilt.com/petro_2.htm

Now, my guess is that Lucas Oil Stabilizer is a mixture of polybutene and some EP, anti-wear and antioxidant additives. The statement that it is incompatible with bromine leads me to believe that it has some degree on unsaturation in the carbon chain. (That's chemist jargon for C=C double bonds).
I have a bottle of Lucas Oil Treatment sitting in my garage waiting to be put into my 91 clattering Club Wagon as soon as the oil level drops ~1 quart below full. Advanced Auto has a neat little display that shows Lucas' ability to remain on gears as you turn a crank that in turn turns two more gears. There is clearly a more viscuos film clinging to the oil treated gears. My guess is that this film helps prevent metal to metal contact of pushrod to lifter or pushrod to rocker arm, hence the quieting.
For what it's worth, polybutenes are routinely used as Viscosity Index enhancers, so putting them in your engine oil makes oil "thicker" at higher temperatures. It isn't cheap stuff, though, which is probably why Lucas is fairly expensive. (That and all the advertising they do in Drag racing).

 

I have used it before and its ok but isnt worth the money.When you can dump a qt of straight 60wt in their for about 2 bucks and get pretty much the same results