Synthetic lubricants also save fuel, as much as 3 percent over mineral lubes, experts say. “Because of the purity, the molecules are all the same size,” Bulkhovsky says. “It’s like running over multiple ball bearings. It’s smoother than mineral lube.” Citgo Petroleum Corp.’s Mark Betner describes this as a “lower coefficient of friction.” In other words, synthetics’ superior “slipperiness” reduces the amount of power required to turn the gears and bearings so the engine uses less fuel.
Another factor contributing to fuel savings is that synthetics maintain their viscosity – even at low temperatures. “Synthetics flow better at a low temperature because they do not crystallize when cold,” Zakarian says. This means they “allow quick lubrication of critical parts upon start-up in extremely cold climates,” says Reggie Dias, director of commercial products for ConocoPhillips Lubricants.
Better fuel economy, enhanced component life, reduced maintenance costs and longer warranty terms are just a few reasons why using synthetic lubes could be a good choice for your business. “We feel like we are saving a lot by reducing downtime and extending our warranties,” BRT Transport’s Mast says.
All lubes qualified for extended use and warranty, whether full synthetics or not, offer superior performance in over-the-road applications. However, if you run off-road or in other unusual circumstances where there is a problem with fluid contamination – from dust, dirt and moisture – you’re probably smart to stick with traditional mineral lubes and shorter change intervals.
MUCH OF THE BANG FOR FEWER BUCKS
Still worried about the high price of synthetics? You can get most of the benefits of synthetic lubes at a lower cost with products from makers including Citgo, Chevron and Shell. These highly refined mineral lubricants cost more than regular mineral oils and are not as widely sold.
Called Group II and Group III base stocks, they meet component manufacturer’s extended warranty and change requirements. However, that could be changing. Rick Muth of Roadranger field marketing, which handles service for both Fuller transmissions and Dana Corp.’s rear axles, says that the qualification test for extended changes and warranty will be toughened “to include better performance in low temperature operation and better gear wear and scoring protection.”
Refiners create these “super” mineral lubes using very high temperatures and pressures and special chemical treatments to produce mineral base stocks that are “actually chemically reacted, and altered or modified,” says Chevron Corp’s Jack Zakarian. “It’s a synthetic process,” and even though the final product isn’t built from basic molecules, as is a synthetic oil, it still has a much more uniform structure. As a result, the difference between the two is “a subtle distinction.”
As long as the “super” lube you are considering meets the performance and warranty requirements outlined by your axle and transmission maker, there’s no reason you can’t use it, experts say. Lube makers put these lubricants through extensive field testing in order to have them included on component suppliers’ approved lists. For example, to receive warranty approval from Dana Corp. and Arvin Meritor, Shell put its “super” lube through rigorous lab testing, as well as more than 50 million miles of on-road fleet trials, says Greg Raley of Shell Global Solutions.
There are some very good semi-synthetic lubes for automatic transmissions, though they have been tested only in autos, not commercial trucks, where the lube runs hotter, says Dwight Kramer, OEM development manager at Castrol, a brand of BP Lubricants. He recommends fully synthetic lubes, such as Castrol’s TranSynd, for auto trannies.
THE PRICE OF CHANGE
Even though synthetic lubes cost more than mineral lubes, the longevity of synthetics yields a modest savings of $200 or $300 over mineral lubes over 500,000 miles for do-it-yourself changes. The real economy, though, comes by eliminating the downtime and inconvenience of more frequent changes. Over 500,000 miles, a synthetic might save four changes for axles, seven changes for the transmission. Actual costs and drain intervals vary by application, brand, component capacities and other factors.