How to Choose Between Rotella T5 & T6: Viscosity Grade Rotella T5. Two viscosity grades are available in Rotella t5, which include 10W-30 and 15W-40. It is a synthetic motor oil for your engine but is heavy-duty and built to last. A combination has been used along with some additives in this synthetic oil. Shell Rotella T6 15W40 and 5W40 – (quick overview) 1. Shell Rotella T6 Full Synthetic 15W40 Diesel Engine Oil. Shell Rotella T6 Full Synthetic 15W40 Diesel Engine Oil is a high-quality engine oil with a 5-star rating. It has been designed to provide the best performance in extreme conditions, particularly in hot and humid environments. The main differences have been illustrated below with the help of a table: Being a thin and lightweight engine oil with low viscosity, 5w40 can effortlessly flow between the engine parts. 10W-40 oil is thick and has high viscosity. It provides a more robust protection to the parts of an engine. What is the difference between 15W-40 and 10W30 engine oil? 15W-40 is better for extremely hot conditions such as towing, hauling, and stop-and-go driving. 10W-30 is better for protecting engine components for more extended periods between oil changes. 15W-40 is better for active engine components, like oil pumps and bearings. The 10W 40 oil has a better flowability at cold temperatures than the 15W engine oil. This is because the 15W -50 oil is thicker at low temperatures than the 10W-40 so, it will not flow well at startups. However, it is best at high temperatures because it is thicker and therefore maintains its viscosity even when temperatures rise. In comparison to a 15w40 motor oil, a 10w40 oil is believed to degrade more quickly. This is because the viscosity indexes of 10w40 motor oil are higher. However, this statement is regarded to be false. This is the bane of today’s engines, as it drastically shortens their lifespans. Some sludges will also be present. .

difference between 10w and 15w oil