One thing to remember, in Europe a synthetic oil has to be a true synthetic, not the sudo synthetics that are common place in the USA. Most of the off the shelf synthetics in the US have a base oil of hydro crushed crude, yes it's better than plain old crude but still doesn't perform like a true synthetic.
Yes, I think you're right. My personal view is that a true synthetic shines in a direct injected engine with extended mile oil changes, strictly because of the fuel dilution issues, or in extreme hot or cold conditions. I know some of the old time mechanics don't care for synthetics, they claim they cause cam and lifter issues. Don't know if they really have any proof or that's just their feelings. The whole argument that oil A is better than oil B is pretty much all corporate advertisment. Choose a oil and if it works for you keep using it, if not change to something else.
Full synthetics also don't have the long term corrosion protections as a semi synthetic, or mineral oil.
That's a reasonable statement and I'm not trying to discount it at all, however I think it would depend on the specific manufacturer. I use some amsoil products and they have corrosion tests on some of their products that show better corrosion protection, again this is their advertisements. Then again they're oils are a secret proprietory blend so there's no way of knowing how much group3,4,and or 5 base oils are there other than their claim of 100% synthetic.
Funny you mention amsoil. Their interceptor was the worst for 2 stroke snowmobile oils as having the least protection against corrosion. We disassemble several engines years ago that failed running on that oil. Every one had rust on crankshaft components, and bad rod bearings from being dry. Maybe its been reformulated by now, but we no longer use it.
No I haven't, I've read a bunch of oil analysis data that different people have posted claiming that they're oil is better because. In all the reports the same compositions were reported, a little more of this a little less of that, nothing to really differenciate between a group 3,4,or 5 synthetic. About the only differences was the wear metals which did vary some but it was more according to a particular engine and not the lube used. Someone did make a comment one time where they found out the actual synthetic content of mobil1 but it wasn't readily available. They did some extensive searching and then you had to basically be a chemist to understand what you were reading.
I've heard that about their 2 stroke oil before. I'm not saying amsoil is the best, only that I use some of their products. I run Pennzoil in my engines and amsoil severe gear in the diff. Alternate between Lucas and amsoil for a gas additive. Years ago I used to be 100% amsoil but over time the other companies have stepped up their game, I don't think there's that big of difference anymore unless you are pushing for extended drain intervals.
Basically the gravity effect of pulling the thin synthetic back into the pan when vehicle is shut down for an extended period of non-use... All the upper bone dry!?
I've always used amsoil severe gear oil also. As far as mobil 1 motor oil, its made from base 5 and 6 stocks. The toyota dealer here change's the oil with it, so i'll continue using it.
It depends how long the vehicle stays parked not running. I would think in the right environment for corrosion to happen, those weight synthetics could be a problem for not keeping a good film on those upper engine components if the vehicle isn't used for a long period.
I'm going back to amsoil my next change, I got away from it last year strictly because of price. Been using Pennzoil the last year and it's been ok however my wife's van has an actual oil life monitor vs a mileage reminder. According to the monitor the Pennzoil is done at 5k miles, amsoil was still at 50% at 5k miles. I've used amsoil for years in many different vehicles and equipment and never had any issues. Gonna suck it up and spend a few extra dollars and go back to the good stuff.
I recently stumbled upon some literature stating automakers competing against each other with those sales tactics known as cost of vehicle ownership.
That's also one of the reasons for e15 and e85 gas. It's not that it's better or is good for you're vehicle. I would say most consumers don't have any idea what kind of gas mileage they are getting, the only thing they see is the price on the pump.