Nissan 370Z Forum - View Single Post - 0w-40

secondnissan · 07-12-2011, 04:53 AM

because at operating temp the "40" weight oil is much thicker then a "30" or "20" weight oil. The second number in Xw-XX is the viscosity at 212 degrees . 40 will protect the engine better at oil temps above 230 but will hurt fuel economy.

07-12-2011, 04:53 AM	#2 (permalink)
secondnissan Base Member Join Date: May 2011 Location: chicago burbs Posts: 70 Drives: 10 370z 7at Rep Power: 14	because at operating temp the "40" weight oil is much thicker then a "30" or "20" weight oil. The second number in Xw-XX is the viscosity at 212 degrees . 40 will protect the engine better at oil temps above 230 but will hurt fuel economy.