Q & A: Are We There Yet?

The ultimate engine oil question. . .


The term ‘Shell Lubricants’ collectively refers to the companies of the Shell Group engaged in the lubricants business. Shell lubricants companies are global leaders in lubricants and operate in approximately 120 countries worldwide. They manufacture and blend products for use in a range of applications from consumer motoring to food processing and heavy industry to commercial transport.

Q: I was at the TMC Meeting in Orlando this year, and I heard a lot of my fleet maintenance colleagues still asking questions about what fuel and engine oil they should be using now that they’re finally buying trucks with EPA 2007 engines. I thought all those questions about ULSD and CJ-4 oil were settled a long time ago! Did people wait so long to buy 2007 trucks that they don’t remember what to put in the engines? What’s going on?

A: During the meeting of the Technology and Maintenance Council (TMC) in February 2008, I also attended a number of seminars and appreciated the dialogue that took place among those attending. As you say, there were a number of questions and some confusion as it related to the use of API CJ-4 engine oil in 2007 emission and pre-2007 emission engines. We also discussed the relationship between CJ-4 oils and the change from Low Sulfur Diesel (LSD) to Ultra-Low Sulfur Diesel (ULSD) fuel. The changes in engines, fuel and engine oil all occurred at about the same time in late 2006 and early 2007, which has resulted in numerous questions about how all these elements worked together.

Let’s start with the changes to engines. The 2007 emission standards for heavy-duty on-highway diesel engines involved changes to engine hardware, including the addition of after-treatment devices such as diesel particulate filters (DPF) and in some cases an oxidation catalyst.

In late 2006, most marketers of on-highway diesel fuel began selling ULSD fuel, which is defined as having less than 15 parts per million (ppm) of sulfur. ULSD replaced LSD, which can contain up to 500 ppm of sulfur. ULSD fuel is required to ensure correct functioning of the 2007 emission engines. The combination of after-treatment devices and ULSD helps to dramatically reduce emissions. Developing new diesel motor oil was essential to meet the needs of low emissions engines and to help maintain the durability and performance of the DPF.

The American Petroleum Institute (API) created a new engine oil specification, CJ-4. The specification was designed for use in 2007 emission engines as well as pre-2007 emission engines. CJ-4 motor oil was developed to provide optimum wear and deposit protection, as well as soot and high temperature (oxidation) control. The oil also protects against foaming, aeration and viscosity loss due to shear.

Additionally, the CJ-4 category has limits on the sulfated ash (the residual ash derived from burning the engine oil) content of the oil to help maximize the service life of the DPF. CJ-4 oil provides a giant technology leap that goes beyond the protection offered by CI-4 PLUS. CJ-4 oils can benefit 2007 engines as well as pre-2007 engines when used in conjunction with ULSD.

Throughout the TMC meeting, the question of whether CJ-4 category motor oil can be used in pre-2007 emission engines was also raised. The answer is yes; CJ-4 engine oils can be used in pre-2007 engines. CJ-4 can be used in engines that originally required the former engine oil performance categories such as CI-4 Plus, CI-4, CH-4, CG-4, CF-4. Most engine manufacturers allow engine oil drain intervals to remain at current levels when using API CJ-4 engine oil in a pre-2007 engine and when using ULSD. If you are using LSD, you will want to contact your oil supplier or OEM to confirm the proper drain interval.

CJ-4 oils, such as Shell Rotella® T motor oil with Triple Protection™ technology, are designed to provide improvements in wear protection, high temperature oxidation control and soot handling required by the new engines. API CJ-4 motor oils are also designed to optimize the durability and performance of DPFs. Overall, the lower ash content in the oil will mean the DPF will potentially need to be cleaned less often, which can mean lower maintenance costs.

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