Of course the manual suggests 0W-20 and I’ve followed that (ac delco 0w20) for the last 3 years since it’s new. Last time a mechanic told me I should never use the thin 0w20 since where I live there is no winter and it’s only for US. Our summer is very hot and I mean it reach 50 C (120 F) degrees in July and August. In winter temperature never goes below 3 C or 40 F and that’s even rare. Last time I used the Mobil 1 0W40 Euro but it’s too expensive ($14 Quart) and didn’t notice a difference. Should I try SHELL Helix Fully Synthetic? Or maybe 5W40 or Castro’s Edge 10W-60?