I once stumbled upon a forum where turbo Subaru owners were doing oil analysis on their used oil. They were running either a Mobil 1 5W30 or 10W30 and seemed to be showing excessive wear based on the metals content of the oil. Somehow someone came up with the idea to run the Rotella T6 5W40 synthetic and the wear rates went down dramatically. I think these were tuned cars putting out more power than factory and being used for rally racing purposes.
The Rotella T6 oil DOESN’T meet the required API specs for the Subaru in question so wouldn’t be valid for warranty claims. That being said, I am sure that tuning your car like that would also void warranty claims. I run this oil in my mowers and have been very happy with its performance, especially with how hard I run my mowers.
I think I noticed that Fleet Farm has the Resolute brand called full synthetic for about $2.40 a quart compared to $6 for Mobil 1. I strongly suspect it is recycled though on the fine print on the bottle. I’d never use it for anything.
I just went out and looked at the quart of RK 0W-20 full synthetic oil I bought for $2.69 at Rural King. I found nothing on the label indicating that this is re-refined oil. Unfortunately, somehow the bottom of the jug got punctured and when I picked it up, oil started leaking out. The plastic container looked compressed. I’ve never had this happen before. I think I bought the quart last fall and it has been on the shelf unopened since that time.
@Triedaq
" I found nothing on the label indicating that this is re-refined oil. Unfortunately, somehow the bottom of the jug got punctured and when I picked it up, oil started leaking out. The plastic container looked compressed. I’ve never had this happen before."
Perhaps only the container is cycled? CSA
@"common sense answer I did recycle the oil. I poured what was left of the 0W-20 full synthetic into ,half filled bottle of 10W-30 full synthetic. I’ll use it in my old lawnmower that uses a lot of oil. I’ll use it to top up the oil. When I change the oil in the mower, I’ll go with the full synthetic 10W-30. I am back to using the old mower. I bought a used rechargeable battery mower a couple of years ago from a friend. I had to put new batteries in this spring and now the new batteries are going bad. I know the charger is working. Oh, well my gasoline mower is on its,25th season. If I break down and buy a new mower, I’ll use the 10W-30 full synthetic in it.
@cwatkin I added the 0W-20 synthetic to a,quart container that contained 10W-30. When I calculated the viscosity of the resulting mix, I calculated that I have 7.093W -26.87. I figure that when I used to use straight 30 weight dino oil, the viscosity was reduced by the unburned gasoline that slipped by the rings.
I notice that there are some who still believe that synthetic oil is merely a more highly refined dino oil. That’s totally untrue. It’s made from highly modified molecules of a variety of substances which I will not go into again. Pennzoil is even made from natural gas (see attached image).
Edit: See the blue print under “full synthetic” You’ll need to enlarge (click on) the image.
“I notice that there are some who still believe that synthetic oil is merely a more highly refined dino oil.”
In the US there are highly refined dino oils that are legally described as “synthetic”.
There are several levels: group II, group II etc. Only group IV and above are “true” synthetics, assembled from non-petroleum base stocks.
The thing is that I don’t see anywhere on the bottles that identifies it as group II, III, IV etc. Maybe its there somewhere but mostly just the API seal and “meets most manufacturer requirements”. Without a lot of research that most of us aren’t going to do, I’ll just stick with a name brand in my ignorance.
True synthetics are PAOs, Polyalphaolefins as a base stock. It costs more to refine and is used by Mobil1 and others. Taking a standard feedstock oil and HYDROTREATING it gives it qualities more like a synthetic, but not quite.
I play it safe and get the real stuff; the small extra cost per years allows me to stop worrying about film strength, viscosity breakdown and other weaknesses of those other oils.
I’m a riverboat gambler and use regular old mineral oil and change it at the before (just) the auto manufacturer’s recommended interval expires. That ends up being between 7000 and 7500 miles for my cars. I drive 108 miles round trip in my commute on the highway. No problems so far.
Chemically oil from crude or synthetic made are the same. They are both hydrocarbon chains. Synthetic oils not made from crude can be engineered easier to make more even consistent molecules. In the long term…unless you’re running an engine extremely hard, or it’s a turbo, or you constantly drive in extreme cold (-10 or below)…then use either oil you want…and after 300k miles there won’t be significant difference in engine wear.
