First off I want to say I figured they would say what they did about viscosity but I do think they did a geat job answering my questions overall and was happy with the synthetic vs conventional oil debate it basically tells me there is zero point in using a synthetic most the time. Here is the entire message they sent me
The recommended viscosity of the oil is set by the manufacturer, and we generally find that it's best to stick with their recommendations when it comes to the oil viscosity. If your car calls for a 5W/30 oil, then changing to a 5W/20 probably wouldn't give you any better wear, and it might make things worse, if the thinner oil isn't thick enough to protect the bearings and other parts that run under a heavy load. Conversely, a thicker-than-recommended oil may not flow through the engine smoothly enough, especially on cold starts, and that could lead to high wear due to oil starvation. So it's not a matter of thicker or thinner oil giving better wear -- it's a matter of finding the right viscosity for your particular engine, and usually we find that the manufacturer's recommendation is the way to go.
We don't typically see a difference in wear metals when it comes to synthetic vs. conventional oil. The general wisdom is that synthetic oil may have the potential to last longer, because it usually has more additives than conventional oil, and that may hold up better over time, but in most cases, the levels of wear metals or other issues will limit the life of the oil before that would come into play. By testing your oil, we can determine if it would be safe to run longer in your engine, but we don't usually take synthetic vs. conventional into account. We may find that it's okay to run longer on a conventional oil, if everything looks good, or we may recommend changing a synthetic sooner, if we see high wear or contaminants
The recommended viscosity of the oil is set by the manufacturer, and we generally find that it's best to stick with their recommendations when it comes to the oil viscosity. If your car calls for a 5W/30 oil, then changing to a 5W/20 probably wouldn't give you any better wear, and it might make things worse, if the thinner oil isn't thick enough to protect the bearings and other parts that run under a heavy load. Conversely, a thicker-than-recommended oil may not flow through the engine smoothly enough, especially on cold starts, and that could lead to high wear due to oil starvation. So it's not a matter of thicker or thinner oil giving better wear -- it's a matter of finding the right viscosity for your particular engine, and usually we find that the manufacturer's recommendation is the way to go.
We don't typically see a difference in wear metals when it comes to synthetic vs. conventional oil. The general wisdom is that synthetic oil may have the potential to last longer, because it usually has more additives than conventional oil, and that may hold up better over time, but in most cases, the levels of wear metals or other issues will limit the life of the oil before that would come into play. By testing your oil, we can determine if it would be safe to run longer in your engine, but we don't usually take synthetic vs. conventional into account. We may find that it's okay to run longer on a conventional oil, if everything looks good, or we may recommend changing a synthetic sooner, if we see high wear or contaminants
