The best engine oil for Maruti Ciaz is the shell HX5 15W-40 which is the fully synthetic if it is a petrol engines and for diesel engines Shell Helix HX-7 Synthetic 5W-40.

“As engine technology and fuel technology have evolved, the environment in the crankcase has changed,” says Stede Granger, Shell Lubricants ... SAE oil grades are defined (15W-40, 10W-30 ...