Passenger Car Engine Oil Specifications

Publishers Letter


In October, General Motors promised its Dexos1 Gen 3 gasoline-fueled engine oil specification would be published this month, followed by a first license date in the second quarter of this year. Gen 2 oils would then be retired by August 31.

This timeline has caused some consternation among lubricants formulators and marketers, who worry about supplying licensed oils within such a tight timeframe.

It seems that GM has heard those concerns. Khaled Zreik, the OEMs powertrain and vehicle fluids technical specialist, told the ICIS Pan American Base Oils & Lubricants Conference in New Jersey last month that internal discussions had turned to an extended timeline, which he expected to be announced soon.

Gen 3 will include new limits on most GM tests, an updated low-speed pre-ignition test and new fuel economy tests. Most European engine tests will be eliminated, Zreik said, and updated base oil interchange and viscosity grade read across rules will be provided. He described the limits for most tests as stricter than those for ILSAC GF-6.

He warned that LSPI persists even with the improvements of API SN Plus engine oils, hence the new test. It is clear that lube formulations designed to meet ILSAC, API and Dexos1 Gen 2 will require detergent rebalance, to say the least, Zreik said.

He also indicated that GM would be far less flexible than in the past, allowing fewer deviations from the official Dexos process.

It remains to be seen how quickly the industry can hit GMs demanding targets. The automaker seems eager to get the newest technology into its engines.

Howard Briskin