Johnson explained that Dexos1 was originally represented by 11 engine tests in addition to chemical and physical tests. We used a combination of CEC, ILSAC, ASTM and proprietary GM tests, he said. GMs interpretation is that Dexos1 exceeded the requirements of ILSAC GF-4 and GF-5 in terms of oxidation control, piston cleanliness, low-temperature pumpability and aeration.

Dexos2 for diesel engines added four tests, including diesel soot control. GMs interpretation is that Dexos2 exceeded the requirements of ACEA C3 in oxidation control, soot dispersancy, piston cleanliness, sludge control and fuel economy. It also exceeded the requirements of API CJ-4 in oxidation control, fuel economy and low-temperature pumpability, Johnson said. To date, more than 200 brands carry Dexos approvals, and more than 100 oil companies are licensed to Dexos.

The objectives of next generation Dexos1 are turbocharger deposit control, aeration, low-speed preignition, piston and chain wear, oxidation and piston deposits, as well as accommodating the new SAE J 300 viscosity grades. This is a unique time in the industry, at least in North America with regard to API specifications, said Johnson. An unprecedented number of engine tests are becoming obsolete and will have to be replaced, including the Sequence IIIG, Sequence IVA, Sequence VG and Sequence VID.

In addition, the M271 sludge test is being replaced by the M271 EVO, and GM is updating several of its proprietary tests. We are working on a bench test for wear, as well as a new vehicle fuel economy test, Johnson related. The test will involve three vehicles – a pickup truck with a V8 engine, a Chevy Impala with a V6 engine and a Chevy Cruze with a 4-cylinder turbocharged engine.

Johnson then summed up the current status of ASTM and GM tests that are being updated. The Sequence VIE fuel economy test is fairly well along in development, but the duration has changed from 155 hours to 200 hours, he noted. This will reduce the number of tests that can be run on a given block, but we expect the test to be ready within the next year.

The engine used in the Sequence VIE is available to the labs from the central parts distributor. However, exhaust valve leakage has been experienced at some labs due to deposit build-up between the valve and seat, Johnson said. Testing has shown that the deposits can be eliminated by using a top-tier fuel additive package, and the fuel supplier is now supplying the new fuel to all labs.

The procedure and parameters for the GM oxidation and deposit test were nearly complete at the time of the presentation. The engine build workshop is complete, as is the engine build manual, Johnson said. The lubricant test monitoring system guidelines have been reviewed by the Test Monitoring Center, and the precision matrix is targeted to start by the end of 2014.

The precision matrix for the GM aeration test was started in September and is targeted for completion by the end of the year. According to Johnson, Eight tests have been run (four on the good oil and four on the bad oil) per engine. Engine aging effects on aeration have been assessed, and preliminary aeration targets have been established.

He said that the GM turbocharger deposit test has been nearly complete for some time. The objective is
to reduce the test duration, but it looks like it will be about 535 hours long. We will monitor turbo temperature during the test and set limits by the end of the year. Two aeration test stands are located at GM, and five other stands are available to the industry.

The precision matrix for the GM stochastic preignition test is complete, and the reference oil precision was scheduled to be completed in October. A test stand is available to the industry for oil evaluation, and Intertek can provide a test overview. Final limits will be announced when the specification is released.

Johnson explained that GM recommends two viscosity grades for Dexos1 users – 5W-30 for its smaller 4-cylinder engine and 3.6-liter V6 engine and 5W-20 for its 2.5-liter 4-cylinder engine. We also recommend using 0W-XX oil in cold weather, he added. John also noted that GM recognizes that SAE J 300 has added XW-16 grades, but we dont use that viscosity in our factory fill oils.

Johnson concluded by saying the licensing program goals for Dexos are to ensure that the right oil gets into the right vehicle, to emphasize the proper viscosity/vehicle match for the installer and end-user, to improve the process for approving suppliers and to monitor oil quality. In addition, the program aims to maintain a long-term sustainable approach to generate revenue for future test and specification development, maintain and monitor the current tests, monitor lubricant quality and educate end-users and installers, he said.