Isn't it the oil companies that are developing the thinner high-pressure synthetic oils, and the cars companies just playing catch up. The thinner oils may not be performing very well (I have no clue about that) but that would come back to the oil manufacturers. Vehicle engineers would be designing engines around the specs provided by the oil manufacturers, it doesn't make any sense they would be just rolling the dice and pouring in their very best uneducated oil guess. It serves the car maker in no way to take the oil manufacturers recommendations and then flush them. Jamming thicker oil into an engine with tolerances engineered for the specs of the $hitty underperforming thinner oil probably isn't the answer either. Another wonderful example of finger-pointing and everyone blaming each other.Value for money 2016 -17 WK 2Grand Cherokee 3 litre diesel .Not Quadralift suspension.Plenty of aftermarket goodies now available for the WK2s.Have a 2012 WK2 and a 2010 WH both been very reliable. I think Toyota have had more combined vehicle recalls than most makes in recent times.Now this DPF saga will be a doozy.Plenty of other makes having similar problems.Owners being told wrong oils being used etc I know a tech guy at Penrite oils.He said in Aust nearly all manufactures are recommending too light a grade oil in their 4x4 turbo vehicles.Hot weather ,towing large vans means more blow by with associated problems