Heavy Duty Engine Oil (HDEO) Frequently Asked Questions

The shelf-life of DEF is largely dependent on storage temperature. When stored under optimal conditions (between 12°F and 86°F) DEF has a shelf life of one to two years. Higher temperatures will not affect the quality of the DEF but will shorten its shelf-life. However, the quality of DEF is not affected if the fluid freezes.

DEF should not be stored in direct sunlight in a shop or in a truck. Prolonged exposure to direct sunlight and high temperatures will cause DEF to degrade, reducing the shelf life. The ideal storage is in a cool, dry ventilated place.

DEF should be stored by batch dates and FIFO (first in first out) system should be used to maintain optimum life of DEF. Drivers purchasing DEF in containers should look for the API Certification Mark when making their choices on products. You should also look at the expiration date on the bottle if present and be sure to use it before this date as the product has a limited shelf life.

In a shop, regular maintenance and testing of DEF should be conducted. Personnel should be familiar with the use of a refractometer which is designed to measure the concentration of water-soluble fluids for purity of DEF. A commitment to meeting the ISO 22241 standard which specifies the quality characteristics of DEF is important to follow.

Ash that is left as deposits on DPFs is produced when small amounts of engine oil are burned during combustion, this is called oil consumption and is a normal occurrence when non-combustible, inorganic material is carried through the exhaust. High quality engine oil like Shell Rotella® can help reduce oil consumption therefore reducing ash and improving DPF servicing intervals.

Oil consumption that leads to higher ash can be caused by excessive ring and/or cylinder wear. All Shell Rotella® engine oils are formulated to provide excellent piston cleanliness, helping to minimize or keep the piston rings and piston lands free from deposits, which in turn helps control oil consumption. For ultimate protection, choose Shell Rotella T6 5W-40 that provides 75% better piston cleanliness vs. industry standard³.

Shell Rotella^® T6 Full Synthetic 5W-40 diesel engine oil offers protection in extreme operating temperatures and resists breakdown caused by heat to provide continuous protection throughout the service interval. Given that the viscosity grade reflects the range of temperatures most appropriate for a particular oil, a 5W-40 will provide both better flow at cold temperatures and increased protection at higher temperatures than a 10W-30.

Shell Rotella^® T6 Full Synthetic 5W-40 also provides excellent protection against harmful engine wear and sludge and resists viscosity loss through shear stability to help maintain optimal pressure in your heavy duty diesel engine. Additionally, Shell Rotella^® T6 Full Synthetic 5W-40 offers enhanced fuel economy capability of up to 1.5%⁴ that can save money in fuel consumption, without compromising engine protection or durability.

Any Shell Rotella Full Synthetic or Synthetic Blend engine oil has gone through a chemically engineered process. Synthetic oil molecules are more uniform in shape with fewer impurities and better properties than conventional oil molecules. In general, synthetic oil has better extreme high temperature and low temperature performance.

Therefore, we would also recommend Shell Rotella^® T5 10W-30 synthetic blend diesel engine oil which combines synthetic base oils and advanced additives to deliver excellent protection, even at low temperatures where the enhanced cold-flow properties help protect your engine. The oil contains Triple Protection Plus™ technology which uses synthetic base oils plus advanced additive technology to provide protection against wear, deposits and oil breakdown. Synthetic blend motor oil uses a mixture of synthetic and conventional base oils for added resistance to oxidation (compared to conventional oil) and provide excellent low-temperature properties.

No matter what you put your engine through, you need to know your oil will protect your engine under all conditions.

Viscosity refers to an oil's resistance to flow. It is the single most important performance property of a lubricant. The smaller the first number, the better the oil will flow when it is cold, protecting engine parts at low temperatures. The faster oil flows to critical parts of the engine and the more they are protected from wear.

So, a 5W-30 will flow easier than a 10W-30 at low temperatures. And a 10W-30 will flow easier than a 15W-40 at normal engine operating temperatures.

Additionally, lower viscosity oils can reduce your fuel costs and CO₂ emissions.

Vehicle manufacturers and many fleets are moving to lower viscosity oils to obtain better fuel economy and help reduce greenhouse gases (compared to SAE 15W-40 engine oils). Lower viscosity oils pump more easily and help to reduce engine friction, which can improve fuel economy. In fact, high quality, low viscosity oils can provide between a one and three percent increase in fuel economy.

Even the smallest increases in fuel economy can result in significant reductions in fuel consumption and carbon dioxide emissions. For example, every U.S. heavy duty truck increasing its fuel economy by just one percent, would see an annual reduction of more than four million tons of carbon dioxide emissions, which is the equivalent of removing more than 20,000 trucks from the road.