Shell Canada says its "new and improved" Rotella T Synthetic 5W-40 heavy-duty motor oil offers significant improvements in wear protection, soot control, deposit control, heat resistance, and protection in extreme climates. It meets or exceeds API CJ-4 specs, and Shell claims it can improve on fuel economy compared to conventional 15W-40 engine lubes — by up to 1%. It gets there through decreased friction and by reducing the energy used to pump the motor oil through the engine. 

That sounds like a small gain, but for a typical truck travelling 160,000 km a year, about 100,000 miles, it means something like 680 litres or 180 gallons. Give or take, thatís somewhere beyond $850.

Shell also says that the new 5W-40 oil showed an average of 34% improvement in wear (ranging from 2 to 90%) in standard industry tests, with substantially improved protection against cylinder-liner wear. This is good news for trucks used for low-speed operations.
 
Better high-performance ashless chemistry helps keep soot particles separated, Shell says, which protects against thickening and helps keep the motor flowing for good start-up and under all operating conditions. The company claims up to a 36% improvement in soot control.

There are gains claimed in extreme temperatures too. The new Rotella T is said to resist breakdown due to high heat, offering up to a 70% improvement in oxidation protection compared to conventional 15W-40 motor oil and up to 81% fewer deposits than the average CJ-4 15W-40. In severe cold, Shell says you’ll see reliable pumping on start-up at temperatures as low as -35C.

The new Rotella T Synthetic 5W-40 formulation is fine with diesel particulate filters on 2007 engines, but itís also suitable for earlier heavy-duty diesels.