Duramax Diesel

GM issued the following press release concerning the 2011 Duramax Diesel's ability to run B20 biodiesel/diesel mix:

General Motors Announces B20 Biofuel Capability For New, 2011 Duramax 6.6L Turbo Diesel

GRAPEVINE, Texas (February 8, 2010) – GM announced today that its new lineup of heavy-duty diesel pickups will have B20 biodiesel capability. B20 fuel is a blend of 20-percent biodiesel and 80-percent conventional diesel, which helps lower carbon dioxide emissions and lessens dependence on petroleum. The announcement was made at the National Biodiesel Conference.

GM’s new Duramax 6.6L turbo diesel engine has been substantially revised to include B20 capability, as well as meet strict new emissions standards effective this year. The new Duramax will power the redesigned 2011 Chevy Silverado and GMC Sierra heavy-duty pickups, as well as the Chevrolet Express and GMC Savana full-size vans. Chevrolet will unveil the 2011 Silverado heavy-duty trucks at the Chicago Auto Show on Feb. 10.

“B20 capability in our new heavy-duty trucks is the latest addition to a growing number of alternate fuel options offered by General Motors,” said Mike Robinson, vice president, Environment, Energy and Safety Policy. “We are seeking different paths to fuel solutions in order to maximize efficiency, reduce emissions and minimize the dependence on petroleum.”

GM already leads in the marketing of FlexFuel vehicles capable of running on E85 ethanol with more than 4 million vehicles on the road today. Like ethanol, biodiesel is a domestically produced, renewable fuel made primarily of plant matter – mostly soybean oil. In pure form, biodiesel lowers carbon dioxide emissions.

“The 2007 federal energy bill mandates increased biodiesel production and more states and municipalities are requiring it,” said Robinson. “Biodiesel production is growing and GM is excited and ready to satisfy demand with our new B20 capable Duramax 6.6L engine.”

Estimates by National Biodiesel Board indicate about 700 million gallons of the fuel were produced in 2008 – up from about 500,000 gallons in 1999. Market fluctuations caused production to decrease in 2009, but it expected to rise with more mandates and the availability of approved vehicles, such as the 2011 Chevrolet Silverado and GMC Sierra heavy-duty trucks.

Validated and approved fuel

Extensive testing and validation was performed on the Duramax 6.6L using B20 that meets ASTM International’s standard D7467, which covers biodiesel blends between B6 and B20.

“True biodiesel is created through transesterfication and that’s what the Duramax 6.6L is designed to use,” said Coleman Jones, GM biofuels implementation manager. “Strict testing and validation was performed to ensure the new engine is B20-capable, however approved biodiesel is the only way to guarantee engine performance and longevity.”

The Duramax diesel is covered by GM’s five-year/100,000 mile powertrain warranty.

To make the Duramax 6.6L and its fuel system compatible with B20, GM upgraded some seals and gasket materials to withstand the ester content of biodiesel and included an upgraded fuel filter that includes a coalescing element. It improves the separation of water that may be present in the fuel, because biodiesel can attract and absorb water. Also, additional heating of the fuel circuit was added to reduce the chance of fuel gelling or waxing that could plug filters.

The Duramax 6.6L’s diesel particulate regeneration system features a downstream injector that supplies fuel for the regeneration process. This greatly reduces potential oil dilution, important with using biodiesel. Downstream injection saves fuel and works better with B20 than in-cylinder post injection.

Duramax Diesel

Joel Paynton asks why most drivers would ever want the clutter of another switch on their dashboard when they already have a multi-horsepower tuning device -- the fuel pedal.

6.2/6.5

Just for fun, here a video of a 1992 Chevy K2500 6.5 diesel as it plows through the snow. Several other vehicles did not make it...

Duramax Diesel

A couple of years ago I was called out by a friend who was using his father's 2005 Duramax to move. It had gone into limp mode on the side of the road. They were towing a small covered trailer at the time. They had many miles to go and were feeling a little let down by an otherwise strong running Duramax. It happened to be close to the end of the work day, so I went out to meet them. I already had a pretty good idea of the problem: the truck could barely make 15 MPH and clattered and rattled like a Cummins (the Cummins faithful love noisy diesels). That symptom typically indicates a terminal fretting problem on either the #7 or #2 cylinder. In my rush to get out the door, I completely forgot all the tools that I might use to nurse the Duramax back home for a complete repair.

Father and son had managed to pull the truck into a side-of-the-road gas station. We fired it up, and sure enough, it clattered and rattled on four cylinders. So I disconnected the #2 and #7 injector wires, revealing the tell-tale signs of fretting on the #2 connector. But how was I going to temporarily fix it without tools? MacGyver would always come up with something using whatever he had available to him at the time. In my best MacGyver imitation I asked for a safety-pin and some WD-40. They looked at me funny, but set about searching hard to oblige. The WD-40 would help to clean off the fretting/arcing residue on the connector terminals and was easy to find - the service station had plenty of it. The safety pin was a little more difficult to find, but necessary because I needed to disturb the terminals so that they exerted more tension on the fuel injector pins. Only a safety pin would be small enough and hard enough to accomplish the task. My friend's mother was the one to come up with a safety pin. After working with the connector, I plugged it back in and started the truck. It ran perfectly. I knew that this was only a temporary fix, the connector would have to be replaced for a more permanent repair. I didn't know exactly how long the repair would hold out, but we could only try.

Turns out that they made it home just fine. In fact, the truck ran fine for several days until we could get it down to the dealer to install a new connector. Just two days after that side-of-the-road MacGyver fix, my friend's father came up to me with a bewildered expression. "How in the world did you fix my truck with a safety pin and WD-40?" I laughed. What made MacGyver so fictionally successful was his broad knowledge base and his ability to improvise tools and materials. A little knowledge can go a long way to get you down the road when you are in a bind. I think most of us have channeled a little MacGyver at least once in a while.

So here's the challenge: send us your best MacGyver moments to get a GM Diesel out of a bind! You can use the comments form below the MacGyver theme video...