what did they pay out -billions- for sludge? this seems like a dubious statement. I would be more worried about your head gaskets or tranny in the long run. I have run non SYN for a while now. while I dont doubt SYM is an improvement, it will not result in higher mpg or any of the other BS claims out there.
I am not familiar with any "BS claims" other than the ones
against synthetic such as causing the engine to leak or synthetic gear oil causing differential failure which are both bogus.
There have been far too many accounts of synthetic oil giving slight improvements in mpg for it to be BS, I have seen that for myself in several vehicles although unfortunately not my 4runner sadly.
So I think it depends on the type of engine and vehicle.
also if you go down to 0W30 from 5W30 then the engine probably has less restriction which I am sure is why my wifes Lexus did so well.
But I have had a few cars give an extra 1-2mpg on average, my 1995 Jeep YJ did, my old 1966 VW Crewcab got 2mpg better plus ran cooler since it was oil cooled, so did my old Baja Bug with a 2180cc VW engine which I fought with for over a year trying everything I could think of to keep it running cool to no avail until I ran Synthetic for my first time in 1977.
I put in a deep sump, a large oil cooler on the roof under a scoop all of which added much more oil and more cooling to it but it still would get too hot, it helped but did not cure it at all.
tried every oil then tried Amsoil 20/50 racing oil and BAM never over heated again never lost power.
Obviously synthetic worked wonders "in THAT vehicle".
Now I use it in my 4Runner mainly because I know it is superior oil with better lubricating properties, does not give me any improvement that I can tell in MPG BUT I know it is a better oil and it will clean my engine and keep it clean and will not sludge up which is very important.
Doesn't cost me a penny more in the long run either so its a win win situation to me.
As for the "what did they pay out -billions- for sludge?"
Toyota had 3.5 Million engines that they agreed to pay for engine replacement for 8 full years under warranty, plus there are up to around 7.5 Million other Toyotas that could also have the sludge problem of which our 4Runners are one of those vehicles.
The problem was like in my wifes Lexus the way the top end was built to super heat the gas and burn off emissions plus burn the fuel more efficiently.
With petroleum based oil REGARDLESS if you religiously change it every 3000 miles or not is moot, because when you turn off the car and the oil flows down a thin layer of oil remains up top where it literally sits there and cooks that very thin layer.
Petroleum oil has a lower flash point than synthetic plus is made up of various size long chain carbon molecules.
The smaller carbon molecules would evaporate and boil off in the form of sludge.
So basically every time you changed your oil you simply supplied it with more small molecules to boil off because it can happen within a few hundred miles.
Synthetic oil does not suffer that problem, higher flash points and all are short chain carbon and are all the same size molecules literally designer molecules made specifically the right size.
The Auto Report: Toyota to Pay Billions to Owners for Sludge Damage