I'm currently using Castrol RS 0w-40 (synthethic)motor oil for my 16v. I've talked to two technicians and both say that this oil is to thin for my motor because it has been driven 190 000 km and that I should use a thicker oil (10w-40 or 15w-40). They also say that if I continue to use such a thin oil I could damage the bearings, cause of the bigger clearance compared to a new motor. Is this true ? Also I think to switch to Mobil 1, is it a good idea ?

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190E 3.0-24v (M104 980) turbo @ 0.8 bar
1/4 mile: 2.483 / 13.540 / 175.17 km/h (street tires)