Motul 6100 Synergie 10W40 is a synthetic-technology blend in the grade that suits a very large share of the South African car parc, particularly higher-kilometre petrol engines and light diesels where a thinner oil can raise consumption or soften hot oil pressure. The 10W winter rating gives sensible cold-start flow, while the 40 hot grade maintains film strength once the engine is working. The 1 litre bottle is the size for topping up between services, or for making up an exact sump capacity when the five-litre container leaves you short. Keeping the matching grade on hand means you top up with the same oil already in the engine. Check the manufacturer’s required specification, not just the viscosity, before filling.