Best Engine Oil for 16v ???

[Jon16]

I have a smooth running, leak free,  but quite high mileage 16v (134k).  The previous owner told me of regular oil changes with Castrol Magnatec.  Should I stick with this or would Mobil 1 or Synta be better?  Just wondering whether Mobil 1 or another fully synthetic would cause problems in an old engine (thinner oil more likely to leak?/burn?)  Any thoughts? Thanks.  

[kevin]

best to use synta silver semi-syn excellent oil for valvers

[Jon16]

Thanks, but the more I read suggests to me that a full Synthetic 0w-40w or something like that (i.e. Mobil 1) would clean out the engine and be much better for cold starts where it will simply flow round the engine much faster as it doesn't need to warm up to thin out?  Not too bothered about the cost of the oil, just looking for the least wear (I understand it has the same viscosity as any other oil once warm).  The car is used generally for reasonably long trips (few short ones), but only occasionally.  Any thoughts or experiences?  Thanks

[kevin]

the point is fully synth is to thin on start up and your engine will be more ratlly, once warm all is fine ,recommended oil for valvers is15w/40
regards kevin

[Jon16]

Thanks Kevin, I'll get some Synta as you suggest