Biodiesel vs 2007 ULS Diesels?

[houdel]

I recently purchased a 2007 Chevrolet Silverado 2500HD LT2 Crew Cab 4x4 pickup with the Duramax Diesel and Allison 6 speed auto trans. A great truck, 365 hp, 660 ft-lbs of torque, this baby can really fly. It is rated to pull a 13,000 lb tag trailer and 13,600 lbs with a gooseneck or fifth wheel trailer. Fuel mileage is pretty good, with about 1100 miles on the odometer the on board computer says my average fuel economy is 18.6 mpg with a mixture of rural highway, expressway, and a little light city driving. On one short expressway trip I averaged 22.5 mpg! Not bad for a 7000 pound truck!

Things are not so rosy when I read the Duramax engine manual though. It is chock full of dire warnings and threats if anything other than #2 ULS Diesel ever makes it into the fuel tank! Some examples:

DIESEL FUEL/ENGINE OIL:
"Notice: Use of diesel fuel other than Ultra Low Sulfur Diesel (15 ppm sulfur maximum) or engine oil other than low ash CJ-4 oil will cause permanent damage to the DPF and related components. This damage would not be covered by your warranty." (DPF = Diesel Particulate Filter) BTW, ULS diesel is available in Canada but not in Mexico.

ADDITIVES:
"Diesel Fuel or fuel additives not recommended in this manual could damage your fuel system .... and engine. Your warranty would not cover this damage." (NO fuel additives are recommended in the manual).

"Aftermarket diesel fuel additives are not tested by General Motors. Some additives, particularly those which contain alcohol or water emulsifiers, may damage your fuel system".

GASOLINE/HHO:
"If gasoline is ever accidentally added to the fuel tank, to avoid severe engine damage, do not run the engine until the fuel tank can be drained."

"Notice: Never use home heating oil or gasoline in your diesel engine. They can cause engine damage."

So much for adding a few gallons of gas to the tank to keep the diesel from gelling in real cold weather. No. 1-D ULS fuel CAN be used below 0 degrees F though.

WEO, WATF Etc.:
"Diesel fuel that has been mixed with engine oil or automatic transmission fluid could damage your engine and emission controls."

I guess it ain't a multifuel either!

BIODIESEL:
"It is acceptable to use diesel fuel containing up to 5% biodiesel (B5) ...."

"Higher concentration (i.e., greater than B5) biodiesel-containing fuels or the use of unmodified bio-oils blended into diesel fuel at any concentration is not recommended and could damage the fuel system and engine. Such damage would not be covered by your warranty."

So much for running my new baby on home brewed biodiesel!

So what is up with all these "do not use ...."? Well, WEO or WATF are probably high in ash content and will clog the particulate filter. HHO probably has a high sulfur content and would destroy the particulate filter. Fuel additives? I guess some could be potentially damaging, but I guess as long as the additive is certified to be 2007 emissions compatible I don't see the problem. Gasoline? Got me stumped here, unless the injection system is so precise that even small amounts of gas will reduce fuel lubricity enough to cause damage. Biodiesel? Really stumped and disappointed here. I WAS planning to run a fair amount of biodiesel in my new truck, I guess it will all have to go into the Deuce.

Anyone have any further thoughts, explanation, clarification or other information on all these "do not use ...."?

 

[Oldvw2]

Sounds like pretty typical manual stuff Lee. I know the guys on the Duramx forums have been talking about these kind of things too. Most guys I have talked to tend to just run some fuel treatment or the factory approved mix of biodiesel while they are under warranty.

The latest engines in a all of the big three have had some pretty major changes for '07 due to the emissions requirements. I wouldn't run ATF or gasoline in any new diesel with their really high injection pressures. Mercedes and VW actually had adding gasline to the diesel in cold weather in their manuals but that was 20+ years ago. My wife's TDI manual reccomends the use of anti-gel additives or winter blend fuel and I have had good luck running Stanadyne brand treatment. I started using it with the 6.2 and 6.5 GM diesels and have used it since in everything (car, pickup, tractor). The latest version on the Standyne Performance Formula is approved for use with ULSD.

I have run B20 in my 7.3 PSD Ford and in the tractor from our local biofuel coop without problems and a buddy of mine was running their B100 in his Cummins pickup during the warm months. Their fuel is washed etc. to meet the ASTM standard.
Hope this helps,
Chad

 

[Goatwerks]

Biodiesel works best in non computer controlled diesels. The electronics on the newer trucks have a hard time with pure biodiesel. GM had problems a few years ago with injector pumps failing at alarming rates and discovered that off road (red) diesel and biodiesel were the cause of most of the failures. Now fuel samples are required when sending in a pump or injector component for exchange/repair.
Can't tell ya what to run, but while under warranty, you would be best to stick to recomended fuels only.

 

[cranetruck]

..."may damage your fuel system"...

Isn't it irritating that they can't be more specific...

 

[kaiser2help]

Bio alternatives

It is certainly not an issue of lubricity as I am sure you know. It is more of a consistency issue. This stuff really congeals in lower climates. can tell you that if you have heating equipment that runs on #2 home heating oil this Bio stuff is a god sent product.

 

[WillWagner]

RE: Bio alternatives

Lee, the other than ULSD won't hurt the engine, it kills the DPF. The soot loading is doubled when anything but ULSD is used. As for the oil, you can use other than CJ-4, but you will need to cut your oil change intervel to about 1/2 of what you do it now..instead of 10k on oil, you need to do it at 5k. Any additive added to the fuel WILL plug the DPF in short order. As for the gas. Ask FedEx what happens when you put gas in a diesel. They bang, knock and, yes it will ruin a fuel system. Most of the components are class fit, meaning very very tight tolerances. Injectors stick. pumps get galled . Also, your engine has a post injection cycle. It will "dose" the cylinder as the exhaust valve opens to get the cat temp up high enough to do the active regeneration of the DPF. Imagine what would happen if you put gas onto the face of a catalyst that was at 750 degrees..

 

[kcimb]

RE: Bio alternatives

DPF? So you mean it will smoke a lot more?

AWESOME! I love a smoking diesel...

 

[WillWagner]

RE: Bio alternatives

No, DPF = diesel particulate filter, NO smoke at all. Only O2, free nitrogens and water out the tailpipe.

 

[TheBuggyman]

If you can afford a bling ride like that, good pump diesel should be a non-issue!

 

[Westech]

RE: Bio alternatives

you don't have to add gas to the duramax in the winter. Its rated to start at -25* below and mine has started at -40* below no problem with no "thinner" in the fuel. You will not want to use anything but low sulfur Diesel, but you can use Diesel 911 and such. Gm always states to never use anything but GM type oil and fuel adds. Its there way to try to scare you in to buying only true GM stuff. But there right on only using the correct fuel.

(many many hours in GM tech training on the duramax)