S2G Bobtail: Positive Reviews With Some Challenges

Freightliner unveiled its S2G propane-fueled bobtail in 2012, making it possible for propane marketers to “run their fleet on the fuel they sell.” The bobtail filled a void that had existed since GM phased out production of its 8.1L engine for the medium-duty truck market at the end of calendar year 2009. Drivers have been delivering fuel since 2013 in the vehicle, which features an Allison 2000 series transmission and a fueling system from CleanFUEL USA. Its 8-liter, 339-hp purpose-built engine is supplied by Powertrain Integration (Madison Heights, Mich.). The engine provides 495 ft-lb of torque at 3100 rpm. Although some challenges have been reported, reviews are mostly positive.

Bill Cummings of Hocon Gas (Shelton, Conn.) noted his company is running two of the bobtails, one at its Guilford location and the other in Norwalk. He has heard reports that the Guilford truck “runs well and fires very well. All propane functions for delivery work well.” For the Norwalk truck, he said that the truck runs well, with no issues starting up in cold weather, and that it does not lose power when going up hills.

But he also reported some challenges. “Sometimes when the temps get around 10 degrees or lower, it starts a little rough, but once it starts it takes 30 seconds to get going.” He also feels that a lower gear for reverse would be beneficial. He added that if it was a 3400-gal. barrel with a full load, he thinks it would not make it up a driveway in reverse.

Mitch Vanover of Miles LP Gas (Owensboro, Ky.) told BPN his company is taking a wait-and-see attitude before buying an S2G because he has heard of issues traveling up a steep grade. “We’re interested, but we want to get all the bugs out. It’s quite an investment, $10,000 to $12,000 more than a regular diesel.”

Steve Largeteau of Esperance LP Gas (Esperance, N.Y.) ordered the vehicle last fall, but has not used it yet because the check engine light was on when his company first received the vehicle. As of January he had still not received the vehicle back from Freightliner.

However, Kenton Sonnenberg, propane equipment account manager for CHS (Inver Grove Heights, Minn.) operates at least two S2Gs and is hearing positive feedback about them.

“So far, I’ve heard start-up is easy and they take less warm-up time than a diesel, and not having to plug engines in is a plus,” Sonnenberg said. “In addition, they’re a quiet and smooth ride.” He is happy with fuel cost, as well. “I recently ran some numbers on the cost of fuel. Based on a terminal in Minnesota, the price of propane is about 80 cents cheaper than diesel fuel when you factor in the federal incentive. With a savings like this, it’s easier to offset a loss in miles per gallon when switching from diesel to propane-powered.”

The two CHS offices currently using the S2G also report the vehicles are easier to maintain because they don’t have to deal with the diesel exhaust fluid system. He has also been told it uses less oil, even though oil change intervals are more frequent with the propane system.

Tim Schweppe of Arrow Tank reports that after dealing with some initial issues that he says are somewhat expected with a totally new product, the S2Gs seem to be on track. “Our most recent bobtail builds are out in the field pumping gas with little or no issues,” he explained. “However, fuel pump issues continue to plague the S2G, as we’ve just received word of a third fuel pump update within the last year. This latest update is in the form of a kit requiring a new hose fitting and electrical connector inside the tank to accept the new pump. Thankfully CleanFUEL is aware of the problem and [is] addressing it.”

In terms of popularity, he stated that of the bobtails Arrow builds, the diesel-powered chassis are still the selected chassis of choice by about a 10 to 1 ratio.

“However, the S2G can be an excellent fit in areas that have logistical challenges such as diesel fuel or diesel service availability,” he noted, adding that Freightliner, Powertrain Integration, and CleanFUEL USA are addressing the issues as they arise and making improvements through updates and service bulletins.

Milt Swenson of Westmor Industries agreed that the S2G is “getting to be pretty trouble-free now,” noting that some of the early issues included the fact that the automatic transmissions were designed for diesel units, but those have been mostly minor problems that Freightliner has fixed. He has heard from marketers that they are happy with it for the most part. “A big part of that, they’ve got the fuel right on-site, they don’t have to drive over to a gas station if they’re a propane marketer only and go get their diesel fuel. They just fill up their unit right at their own facilities.” He has heard that several new diesel engines and some new automatic transmissions will soon become available, and that should increase customer choices.

Schweppe did address issues such as “a learning curve for drivers and fleet managers in terms of driving behavior and finding the resources available to address concerns.” He mentioned a Midwest fleet manager who told him that a “two-footed driver” — driving with one foot on the accelerator and one on the brake — will trigger more fault codes during the day due to driving habits and tight engine control module monitoring parameters. A common situation for the two-footers is having the throttle and service brake active simultaneously — which results in a fault code. He noted that letting the vehicle roll backward while in a forward gear is another habit, whereas when going outside the program parameters will cause the engine to stall. Knowing the cause and making drivers aware of their habits is reducing the number of faults and keeping everyone happy, Schweppe explained.

He added that resources for the fleet manager such as Powertrain Integration’s Web-based service and support is “essential and extremely helpful. Problems can be avoided by knowing the basic preventive maintenance schedules. Change your plugs at 30,000 miles and don’t wait, otherwise you will soon find the motor down on power and running extremely rough. New plugs equals happy bobtail and happy driver.”

“The Freightliner S2G continues to improve and gain sales in the marketplace,” said Tucker Perkins, chief business development officer for the Propane Education & Research Council (PERC), adding that marketers who purchased it have stated a willingness to buy more. He has heard positive feedback from S2G user AmeriGas (Valley Forge, Pa.), and he added that Eastern Propane (Rochester, N.H.) has been a supporter of the vehicle from the beginning and has bought multiple S2Gs.

“I think Freightliner has gained maturity on how to position the propane product,” Perkins noted. “The dealers understand it a little better. So we expect better things out of Freightliner in 2016 as well.” —Daryl Lubinsky