chill guys - all 0w20 oils sold are synthetic oils and are about 35% thinner than w30 oils when at full temperature (better acceleration and economy) however they are expensive (atleast in USA)
Instead of any other customer I'll give you my own 2AZFE engine which was repaired 100,000 kms ago. Its using cheapo 5w30 or a synthetic blend (depending on which I get for free/cheap and a cheapo oil filter which has a store name printed on it). Toyota specced this engine for 5w30 SL in 2002 while the same engines sold in 2008 were specced for 0w20 - the differences found are slightly tighter bearings and oil spray jets under the pistons and a cheaper made cylinder block.
now - as discussed the PCV (breathing) is critical to any engine oil life and so is engine temperature. If the breathing routes are clogged with gunk/sludge/crap your engine oil will become tar. Very simple - if any of you are old enough to remember the toyota 4K had faulty PCV valves because mechanics threw out the thermostat on them which caused the API SC 30/40 oil to become grease overtime jamming the valve and clogging the vent in the tappet cover which would blow the engine seals and render the oil as black tar - to which mechanics used to say "haail 2no. hai"
anyway - YES - Liqui moly are inferior oils to any similar large number production oils sold by Shell, BP, Mobil, etc. I personally buy bulk oil of brands you may have never heard of and have hundreds of thousands of combined driven miles on them (such info is shared among shops/repairsmen here)
Now coming to the google warriors - if you are reading on the toyota sludging engines of USA - its was 80% done by owners themselves as the notion of "toyota never require any maintenance including oil change" was very strong with them. This same bullcrap is now being seen by BMW lease owners who literally drive the vehicles for the leased 30,000 miles without doing a single thing and hand it back to the dealer after the lease is up - They say - its a lease I dont care.
TL;DR - before believing google at face value - look into it a bit deeper.
p.s. - I change the engine lube oil in my khota gaari camry at 5000 miles (8000 kms) - when I recently pulled the valve cover for packing replacement - the surfaces were shiny clean (extreme little varnish). When I repaired the engine. I spent a lot of time cleaning the valve cover air paths as they are hot riveted into the plastic - hot water and industrial cleaner soaking took care of that. - It was clogged badly.
p.s. 2 - always make sure there is no leak anywhere in the engine as it can become an airpath for the breather -the breather should breathe from the filtered air intake tube only - otherwise sludge x sludge = bad news. => fight with wife => forgetting her birthday => worse fight.
