Any oil that's not worth leaving in its virgin state isn't worth buying.
The odds of improving the overall performance of an engine oil by dumping in additives are extremely low. The odds of having an adverse reaction that increases wear and/or deposits, affects seal compatibility, etc is much better.
TooSlick stated above;"Any oil that's not worth leaving in its virgin state isn't worth buying."
Agreed.... and correct in a perfect world or at least a controlled environment.
However, oil analysis and practical observation tells us otherwise.
If that was true Ted, you would have had to return Amsoil formulas of the last nearly 10 years for oxidation issues. Instead many changed the oil out earlier than advertized, added LubeControl to maintain design grade and lower oxidation rates, or those that just didn't sample ( or get an accurate analysis result) allowed needless wear and decreased performance with a thicker, oxidation damaged fluid.
GC 0w30 is such a fine formula that adding anything to it is not "normally" required.
I warn that not taking at least an annual oil analysis is guessing at best.
Periodic Auto-RX cleaning is a good idea because motor oil STILL cannot clean well enough.
Anything else added by my recommendation would be done with analysis telling us what and how much.
Stuff like VSOT - although a fine product, raises the [email protected] beyond the normal recommendations of today's new vehicles. GC is thick at 12-cSt. Adding VSOT pushes that to 13 & beyond.
How many folks feel comfortable with that thick of motor oil - in a day & age where more & more 8-cSt is becoming the norm with 5W-20s popping-up in many new vehicle owners manuals?????
Volvohead, I am just telling the reader what we see in analysis. Brand bullpoopoo aside.
I prefer a jab or combination over a lady like backhand!
Stick with one or the other, no need to change if you use an appropriate vis for the design.
Now that I have YOUR attention....
Synthetic anything will flow and pump easily in most cold weather regardless of the 100C vis. You guys over obsess with vis when the lube is a high quality formulation.
The primary reason I am planning seasonal changeovers is to use my on-hand inventory more evenly. The vis issue wasn't a concern, other than that the RL might put up with the very worst summer temps in a turbo environment a little more gracefully. I would likely be just as comfortable running GC in summer and RL in winter. But I appreciate your guidance and thank you for it.
I was only being understated; by all means jab and pummel away.
That's an interesting backhanded indictment of Amsoil.
Still, I cannot but agree with you that the only sure way to determine the need for, composition and proportion of any ongoing additive dosing is through analysis.
. . .
So, now that I have your attention, perhaps you might offer your thoughts on running GC in the winter and switching over to RL in the summer, generally speaking. You have previously discouraged mixing these two oils in the same fill based on their chemistries. I have posed this question elsewhere with little response. Yes, I know that analysis would be the best answer, but you seem to hint at a more fundamental chemical incompatability between the two. I apologize for any highjack.