Spied! GM's Next Duramax Diesel Engine

Spied! GM's Next Duramax Diesel Engine
LML Duramax Diesel Photo by Brian Williams for Brenda Priddy & Co.

Diesel may be in the dumps when it comes to light-duty pickup trucks, but things are starting to get hot in the heavy-duty segment. New federal emissions rules set to take effect in 2010 have sent Ford and General Motors back to the drawing board to clean up their oil burning engines. (The current Dodge Ram HD and its 6.7-liter Cummins inline-six already meet 2010 emissions standards.)

We’ve previously reported about Ford’s upcoming 6.7-liter, eight-cylinder in-house replacement for the current 6.4-liter V-8 Power Stroke, code-named Scorpion. Now we’ve received new information from sources about GM’s updated 6.6-liter Duramax V-8, plus this close-up spy photo.

General Motors uses three-letter identifiers to designate each new iteration of Duramax. The current 2007-10 LMM Duramax is designed to run on ultra-low-sulfur diesel fuel and work with a diesel particulate filter to cut soot emissions 90 percent from 2006 levels. The LMM’s replacement is said to be called the LML Duramax.

LML 6.6-liter V-8 Duramax Diesel

LMM 6.6-liter V-8 Duramax Diesel

The LML is expected to be GM’s cleanest diesel engine yet. Some have speculated that its displacement would grow to 6.9 liters for emissions reasons, but our sources say it will continue to be a 6.6-liter V-8.

In addition to trapping almost all particulates, the LML will have to cut nitric oxide levels by at least 90 percent from today using urea selective catalytic reduction.

NOx is a major air pollutant that contributes to smog, asthma, and respiratory and heart diseases. It's a byproduct of diesel’s high combustion temperatures, which result from the high frictional heat levels created by compressing air in the cylinders to the point that it can ignite diesel fuel without using a spark.

The use of urea -- which is being sold under the more marketable name “diesel exhaust fluid” -- will require periodic DEF refills during refueling or regularly scheduled maintenance.

But the LML won’t use urea alone to lower NOx. Our sources say the LML will also add a second exhaust gas recirculation cooler to the engine, similar to the dual-EGR cooler setup that the 6.4-liter Power Stroke diesel uses.EPA Emission Standards for Diesel

EGR recirculates a portion of the engine's exhaust back into the engine at a lower temperature. The cooled gases have a higher heat capacity and contain less oxygen than air, lowering combustion temperatures and reducing the formation of NOx.

Like the LMM, the LML Duramax is expected to stay with a single variable vane turbo, but the wastegate plumbing for its exhaust appears to have changed considerably compared with the older engine. This is likely for emissions reasons.

When the original 2001-04 LB7 6.6-liter Duramax V-8 debuted, it helped pioneer the use of solenoid-controlled common-rail fuel injection in HD pickups. The LML is said to be upgraded to state-of-the-art piezo-electric injectors, which can react faster to fuel demands than solenoids can.

One of the major innovations of GM’s now-shelved 4.5-liter V-8 “baby” Duramax was the use of compacted graphite iron in the engine block to keep weight down and increase strength. For now, the LML is expected to stick with a conventional, heavier gray iron block.

In the photo, you can see the LML test engine has two alternators. We believe the second alternator will be an option for certain commercial applications, like ambulance prep packages.

The same aluminum heads used in the LMM and LBZ Duramax engine are said to continue unchanged, though the pistons are expected to feature a new oil-flow design to improve temperature control.

2011 Chevrolet Silverado 3500 mule
2011 Chevrolet Silverado 3500 mule by Chris Doane for Brenda Priddy & Co.

Almost a year ago, in the first spy photos of 2011 Chevy Silverado and GMC Sierra heavy-duty mules, we noted that the inlet in the middle of the front bumper that feeds air to the truck's transmission oil cooler was about a third larger than the current inlet. We wondered what changes GM might be planning for the Silverado’s Allison transmission and EGR system. Our sources say the LML will continue to use a six-speed automatic. Some work had been done experimenting with an eight-speed automatic for improved fuel economy and towing performance, but it’s said it was determined to be too costly. The large inlet is likely due to increased use of EGR and what’s said to be major changes to the Allison gearbox’s torque converter.

We expect power ratings for the LML Duramax to be approximately 700 pounds-feet of torque and 390 horsepower.


This is old tech from GM if they stick with grey-iron. Navistar just came with the news that they have Compacted-Graphite Iron Block in the brand new 6,4 litre MaxxForce 7.

How can MaxxForce deliver outstanding fuel efficiency, emissions control without SCR, quiet operation and maximum durability? The answer is the industry’s only Class 6-7 CG Iron block. This incredibly strong platform handles the highest fuel pressures that deliver the best fuel combustion and damps vibration and noise. It carries the load without weighing you down.

Strong as a rock, light as a feather.

Because CG Iron is so incredibly strong, castings don't have to be as thick and heavy in order to achieve the desired structural integrity and durability. This results in 45-pound crank weight reduction (net 20-pound engine weight reduction) over a comparable V8 engine cast from gray iron - which further improves fuel economy.


When GM sold off Allison Transmision to Onex and Carlyle, they kept the Baltimore plant where these transmisions are made. My question is how can they keep using the Allison name? And won't that hurt sales if they don't. The Indianapolis plant makes the same transmission and is now under the Allison Transmission Inc. name.

Obama doesn't know how to build a truck.

OK but does it still use the Chevy LUV suspension up front on the 4x4's ?

Notice the fact there are two altenators and a high amperage wiring. I am wondering what is going on here, maybe a hybrid system of some sort, maybe start/stop. The fan on the new model is larger and the placement of the upper radiator hose and throttle body indicate the possibility that the heads are reversed like in the baby max. The large filler tube in the upper left coner also tells me that this Allision is more than likely a segment busting 8 speed. I think GM came to play and will increase it's GVWR to 30,000 pounds with this setup.

@Anthony: Totally agree. I mentioned the two alternators in the story. This engine's setup could be to test out a high-power-needs application, like an ambulance prep pack, but I'm leaning towards big time transmission changes. Still six gears but all new kind of torque converter.

i sure hope they beef up the chassis, otherwise I si this as waste to HP and torque ....it's got to a least pull 18-20K!

So Cummins is already 2010 compliant without this Urea crap??

Why is GM so far behind??

Looks like it's finally started to be more exciting in the heavy duty pick up trucks with diesel engines... I'm looking forward for the final results of those domestic truck wars, especially for the new look of the all new FoMoCo F250 and above HD truck series!

Urea is already being used in the Cummins, it is the only way any Diesel can pass the new requirements. My question is why school buses are still not required to meet these requirements. I was sitting behind a bus as it took off and left a black cloud. Kind of a double standard...

@ Anthony

The ISB6.7 used in the Dodge Ram does not use urea to meet 2010 emissions. It uses a NOx absorber, which has no need for DEF. Dodge has stated that they intend to continue the current setup on the 2500 and 3500 for 2010, but the 4500 and 5500 will use DEF with an SCR catalyst.

As for the school bus, it must not have had a DPF installed. Many municipalities are installing DOCs and DPFs on engines built prior to 2007, but there is a lot of cost involved. If its an old bus, they'll probably just wait and replace it.

Ok, The GM is STILL an ISUZU! Enough Said!

Dual alternators have been an option on Duramax equipped trucks for several years. It is an option used by ambulance upfitters and others needing 200+ amp charging systems. Ford offers dual alternators on some Powerstroke equipped trucks as well. Nothing special.

Orange cables....hmmm.....diesel hybrid? Aren't the thick cables orange on the hybrid 1500s?

53 repairs on my 03 dmax including 3 sets of injectors would keep me far away from any GM truck.

No all new Super Duty coming! 2011 gets a minor restyle, with the new 6.7L diesel and 6.2L gas engine.

BTW Ian, you should have seen this F-150 company truck I had a few years ago. Everything that could have gone wrong, did go wrong! You would be well advised to stay away from Fords too.

So what you're saying is he should stay away from the best selling, safest, strongest, and highest quality pickup in the F-150.

Pickuptrucks.com reported the 2011 SuperDuty is getting a MAJOR styling update and major powertrain update with a new engines and new transmission.

I am guessing the blue filler is for urea?

Jim, don't fall for that 'initial quality' garbage that Ford (and some others) are spewing. It's total B.S.! Take a look at the truck 5 or 10 years later.

If you looking for the best truck, just check Motor trends HD truck shootoff. Funny how all the ferd guys forget Gm wins every year. As far as which trucks last, Quality is so high now with all the big 3, it really comes down to proper maintenance and quality fuel. You can't blame a truck for breaking down if it hasn't been kept up. With todays high pressure common rail fuel systems poor quality fuel will quickly damage any brand fuel injector, and that can't be blamed on any manufacturer. It would be nice to see a hybrid duramax, 6 or 8 speed. You know these trucks are really built well when people are complaining about squeaks and rattles on a diesel truck, hello, it's a diesel truck it's supposed to be noisy. fwiw dual alternators is only a $200 option, and it's nice to charge the batteries on the camper.

"So what you're saying is he should stay away from the best selling, safest, strongest, and highest quality pickup in the F-150.

Pickuptrucks.com reported the 2011 SuperDuty is getting a MAJOR styling update and major powertrain update with a new engines and new transmission."

It's natural that Ford is putting MAJOR styling and major powertrain updates in the 2011 truck - they're attempting to fix all the flaws...

Yup, seems the updates are to fix the Super Duty flaws. For instance, the Peugeot designed 'Scorpion' should fix all the illin' from those craptacular Cornbinder diesels Ford has been using, the 'Boss' should address the chronic low power of the 'Triton' gas engines, IFS will finally get rid of the tire wear problems of Twin-I-Beam and the shimmy problems of SFA 4X4, no more manual transmissions will help Ford owners that don't know how to drive. All steps in the right direction if you ask me!

I love when you buy something small like a computer or a TV and something goes wrong with it, we take it back and get another one. But when people get a vehicle that's bad they damn the company. There is always going to be a few that gets through that shouldn't get out the door. 53 repairs! I think after the third time I would yelled out the lemon law and forced them to give you another one. As for the school busses, I don't see anyreason why they can't use the EV transmission that some metro hybrid busses use. Except the price but, it pays for itself in repairs. I would think we would want to lower emmisions around kids.

As far as the GM winning every year Motor Trends truck of the year.... Thats because GM Sponcers Motor Trend! You are going by someones Elses opinion. Try them all out! Buy the one YOU like the best! Who cares what the other guy has as long as you like what you have got!I'm a Ford guy! I can buy Ford Cheeper then I can buy GM in my area. Yes I've had problems with my 6.0l Diesel, But I owned GM trucks too! And MANY problems occured with them as well! DuraMax isn't the best unless YOU hyave one and are satisfied! I personally think that Dodge has the best diesel, the Cummins! They've been around a long time and they arn't having problems that the GM and Ford are having. But again... That's just MY opinion!

How much will the 2011 silverado tow?

GM sponsors Motor Trend??? I stopped reading that mag cause they did nothing but condemn them. IF it was sponsored I would think it is my an off shore manufacture.

relax all you naysayers and chevy haters...come up with all the excuses and bashing you want about it being an ISUZU engine, or some mindless, baseless rant about poor quality, there is no other truck manufacturer who still has more percentage of their trucks sold, still on the road. Do they only sell to drivers who promise not to total it out? lol...think people. And who brought you the 350? Free your mind, start over, do your research and realize, Chevrolet is the best. It may be a joint venture design with Isuzu, and that's not a bad thing. It has more torque, and will last longer than the others. Say something bad about Allison...go ahead. None? Thought so. Also, Dodge doesnt' make the CUMMINS. Wake up. It's about the final product, and they were smart to use the Duramax. CHEVY OWNS

I don't know much about long lasting yet, but I have a 07 gmc lmm and no Dodge or Ford around my area wants a part of it! Duramax dominance

Love my LBZ. Always will...even after i'm the first guy on the rd in North America with a Million miles on it...I just dont think that any of the others have a chance to even coming close.

Got a ways to go 150k now...running like a top.


Isuzu is (since they started, have been) the best diesel engine manufacturers all-around. They really stand out in reliability. GM makes the best V8. They have worked together to create a powerful and reliable Diesel. Ford knows whats good too. Maybe Dodge will come around soon. Dodge has an inline 6 to work with and they are so behind in their performance technology area that they can't even beat a V8 diesel... that says something about Dodge. They have all the right equipment and still Ford's new 6.7 and GM's LML will be more powerful and honestly probably more reliable, too. I want to see Dodge make it, because an American company shouldn't have to go down, but they need to make some serious changes.


i have a 94 gmc (gas) 230,000 miles doesnt leak or burn oil. still gets 12 miles a gal and I carry 900 lbs in the back always. had 5 fords and 1 dodge, never again!

Cant wait to buy a diesel gmc

I hope gm will get it right this time . the 6.6 is a good motor but the new ones are a bitch to work on ... and can't the get away from all the plumbing I mean really come on , ford and dodge dont
have that much plumbing . They need to figure out how to get away from the dpf filter or redesign it becauses they plug up. Also do something with the egr and all the codes . Come on gm design this diesel right this time . It's not a bad motor just not mechanic friendly . 03,05,06 were good you could tune them and they would run really good .

I have a 2005 duramax its been great it has just a little over 100K and gets about 16 MPG love it. All by another if it ever craps out. might be awhile lol.

relax fellas! their all fords! Henry ford started it all ,here in the u.s.a.

I work in the diesel engine parts business, and I can tell you hours of stories. Here are the facts: Ford has more problems with their engine than anyone else. The 7.3 powerstroke was by far Ford's best engine. GM products have the fewest issues of any diesel pickup. Dodge is in the middle. The most common cause of failures: lack of maintenance and water. Change your fuel filters every 15k miles. Add on a 2 micron Racor 230 if you can. Run a good additive in your fuel. Change your oil on schedule. Today's Higher Pressure Common Rail systems are much more sensitive to moisture and asphaltines. This is not your old 6BT or 7.3 IDI or 6.5 Turbo engine. As for you 6.0 or 6.4 liter guys, good luck. It is only a matter of time before the FICM, IDM, injectors, or EGR system craps out. I can only hope the 6.7 liter is a better engine. By the way, take a 4BT Cummins, drop it in a Jeep and get 26-28 mpg. Love the old stuff.

I have an 07 d-max lbz as my personal vehicle and an 08 6.4 powerstroke as a work truck. They both haul the same weight all the time, but the D-max will smoke the powerstroke in all areas! Ride, comfort, brute strength and mileage. This is not an opinion. They both have about 40k miles and the d-max gets 20 mpg and the Ford gets 12 mpg on a good day. The d-max is also a crew cab compared to the extended cab ford. 0-70 mph in a flash with the Chevy and still waiting in the Ford.... All I can say is Duramax and Chevy have got it figured out!

I have a 93 dodge turbo diesel. Do not question the cummins. I will see an older ford diesel, but ONLY once I have a seen an old chevy diesel. Sorry their diesels are just converted gas engines.

To all the Cummins Engine is like 41% owned by Ford Motor Company and the DMax is designed by one of the oldest Diesel Engine Company's around Isuzu Motor's which GM is got part ownship in. An for Ford they were dummies for not useing the Cummins Engine in the first place in their trucks. I hope the 6.7 is a better Diesel engine than the 6.0 and 6.4 were; they were a piece of junk, they did not have power enough to pull even a 16ft alum. boat


Ford does not own any part of Cummins; let alone 41%. The top holder of Cummins is State Street at 7.39% of the company.

I have a 02 gmc with 6.6 duramax it has 208,000 miles I use "lucas" fuel lubrication in every tank. No engine problems at all. No leaks engine or trans., 16 mpg average pulling backhoe at times. Cant see getting rid of it but when it does give up in another 200,000 or so, I will buy GMC again duramax is the only way.

To all those ford fans out there, that isuzu still will out last your ford. Everyone knows that a ford is just amateur version of a dodge. the cummins is a sissy compared to the durmax. if it wasnt for all the dumb standards that durmax has to comply to it would out haul any cummins any day. If only there was a hybrid diesel for better fuel economy we would see it on more city streets. Lets admit that fuel prices suck! Now a better frame and suspension would be great for its towing cap. we all ready know it has the horsepower and torque. To get that to the road is another question GM needs to solve.

I have owned 3 Duramax pickups in 8 years for a total of 220K miles and have only replaced a window switch on the second truck. The first two trucks were traded in order to stay under the 3 year bumper to bumper warranty. The third truck I still use and will continue to use because I now have learned how great the truck is. Also, I am contractor pulling a 10k load daily. GM "rocks" ! I love my truck.

Good for you Scott! My truck has been with me for almost 15 years, though often times I overload it since I have my construction enterprise that accommodates many customers a day. The only secret I have is to assure the maintenance. If ever I notice something wrong with its parts, I usually check it and replace it if necessary.

I have just purchased a 2011 6.6 Dura Max LML and am more than happy with it. I drive a truck for a living with a Cummins in it and I know that my 2500HD has more power . I did alot of research before this purchase and talked to a multitude of diesel mechanics and believe I have made the right decision.It'll pull 17,000 and that'll do it for me. Go Dura Max.

guys, yall can bicker all ya want about which engines are junk, whos is the best and which are gonna break down. but dont knock it till you tried it. im a ford guy personaly. but that dont mean that anything with a blue oval got my vote. chevy, dodge or ford, they all got some lemons. i personaly feel dodge got the better end of the deal with life time rights to cummins. but its a shame to put such a great engine inside a truck thats bound to rot away around the motor. knock cummins if you want, you can work em like a mule. they run forever. ive seen one with 1,300,000 miles on just regular maintance. easy power. inline is the way to go.(my oppinion). but as for gm guys, yes, duramax is a great motor. but jus cause you got a bowtie tattooed on your forearm dont mean their the best there is. yes, they win the majority of the tests out of the big three. but they got issues to. its easy to get a motor good and crisp when you used basicly the same thing for over a decade and jus make minor changes. but im not baggin on their methods because theyre smart for doin that. they know what theyre doing. as for ford.... knock the 6.0 all you want it's pretty much like scratchin off a lottery ticket. its all in which one you get. some of them are gems, and some arnt worth their price in scrap. but you can fix anything on them and prevent any problems. its allllll emissions. with any diesel. thats what's gonna cause alot of the problems. unless its not stock. and to whoever said that gm diesels are just converted gas motors..... read some more. the only one that was a converted gas motor was the 350. it was the most pointless diesel truck engine ever. but as for the 6.2 and the 6.5, that doesent apply. their great engines. not power houses. but they can last and for what they are, there not too bad. but gm was way behind on their early diesels and im sure many of you can agree on that. however, ive seen many 6.5s in pulling comps and theres alot left on the road. fords new 6.7 i dont know much about but i havent heard anything bad yet but i also havent used one so i don't know. ive worked on and worked with just about every diesel ever put in a pickup from the late 70's to the 2011 models. and in MY OPPINION... cummins is the way to go. the ultimate powerhouse, simple desing, easy to work on, good fuel milage, easy to get power, lottts of torgue, and theyll last forever.

2012 Duramax 6.6 LML DPF Delete Duramax 6.6 forever :)

I love the smell of diesel in the morning
I grew up on a farm and for workhorses the inline 6 diesel was KING.
The Cummins on an alison transmission would blow every other unit out of the water.
To keep any diesel alive :
1. clean oil ...regular good oil and filter changes use best filter you can find
2 clean air - air filters are critical
3. clean fuel that means dirt and water are your enemy 2 stage filtration is absolutely the best.

I currently drive a GMC 07 classic and it runs beautifully
I have a friend with an 06 Dodge and it runs great.
he does get better fuel economy pulling but the unit is also noisier. The Fords in my area have suffered significantly since the termination of the 7.3 l
We have temps from -40c to +40c for our operating temperatures

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