Castrol recco's 10/40 in semi syn magnatec or 5/30 edge in full synthetic, penrite says use 5/40 in full synthetic, shell says use 10/40 in semi syn or 5/40 or 5/30 in full syn, Nulon says 5/30 or 5/40 full syn,
* so overall, it seems a 5/40 is recco in a full syn or a 10/40 in semi synthetic.
The question is, is a 10/50 full syn ok to use on a motor with over 200,000ks on it.....or should u stick to a max 5/40 full syn. Thinner on start up n ok for hot weather. Yes, 10/50 full syn is thicker on start for a med mileage car at 200ks plus but is it too thick on start up, and is the 50 too thick on std running temperature or does the thicker 50 suit such hot aussie summers with hot turbo etc.....any mechanics or motor builders on here or someone who has spoken to a turbo or engine builder ??? Thanks.
