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Old 06-09-2017, 07:15 AM   #1
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Favorite Duramax Engine?

I know I might be opening a can of worms here, but, I'm thinking about upgrading from my 2004 Chevy 2500 with the LB7 Duramax. A friend has the 2007 LBZ and has had no problems. I have replaced the injectors twice on my LB7, once at 110,000 miles and again at 175,000. I know that some people have reported problems with some of the other engines, my question - what is the consensus of opinion on the most reliable? I pull a 2014 Durango 1500 scaled at 9500 lbs loaded, plus a boat or ATV trailer at times. Thanks for weighing in.

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Old 06-09-2017, 07:49 PM   #2
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I don't profess to being an expert on D-max. I was under the impression that the LBZ was a slightly DE-tuned (lower max RPM, -50HP & Ft.Lb) version that was equipped in the MDT (class 4) cab / chassis lines, I'd expect it could be more reliable, but haven't owned one.
Didn't GM finally admit to issues with the LB7 injectors (corrosion) and decide to start warranting them for longer periods?

Best of luck

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Old 06-10-2017, 05:48 AM   #3
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Yes, GM came around on them and upped the warranty to 10 years or 200,000 miles. mine was 11 years old when first showed up, just out of the extended warranty
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Old 06-11-2017, 02:52 PM   #4
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Originally Posted by Tightwadted View Post
I know I might be opening a can of worms here, but, I'm thinking about upgrading from my 2004 Chevy 2500 with the LB7 Duramax. A friend has the 2007 LBZ and has had no problems. I have replaced the injectors twice on my LB7, once at 110,000 miles and again at 175,000. I know that some people have reported problems with some of the other engines, my question - what is the consensus of opinion on the most reliable? I pull a 2014 Durango 1500 scaled at 9500 lbs loaded, plus a boat or ATV trailer at times. Thanks for weighing in.
Used to have an 06 2500HD with the LBZ. Waited to buy it based on the issues with the LB7. Son now has it with just over 100 miles and tows his 34' toy hauler 5th wheel. Zero issues with the engine. If you can swing it, it would be a great upgrade.
2004 Fleetwood Excursion 39S
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Old 06-11-2017, 09:30 PM   #5
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I will keep this short, I went from an LB7 to an LML (2016) and it is night and day! The only thing that I don't like is the re-gen, it happens once a tank and kills your mileage. The new truck is so muck nicer that the old one for power, but the seats don't seem to be as good IMO.
2008 National SurfSide 34E (Bunk Model) Ford V10
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Old 06-12-2017, 12:00 AM   #6
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I have the same experience as you and DDD.

I had an '04 3500 dually, CC, LT with the 6 speed manual. It had cold air intake, FASS and Edge programer. With my roughly 10k loaded gooseneck I would average about 14 and empty I could easily run low 20's.

I had done injectors x2, had the transfer case with the bad "clip" wear a hole and had to be replaced. I bought it used with 100k and I had almost 250,000 on it when I sold it. I was due for tires, felt like the clutch was getting bad, suspension getting soft, just lots of little broken or worn items. Never left me feeling very confident that I would not be dumping lots more money into an old truck.

Back in November I found a new 2016 LTZ version of the same truck, but not manual, for a price I was willing to pay. The new truck is amazing. It is so much more truck then what I had before in terms of pulling power, quiet, smooth and my favorite is the engine break.

The only 2 things I don't like are the payment and fuel milage. I just broke 10,000 miles with at least 50% of that pulling something and my overall average is 12.1 MPG. When doing trip milage pulling it is not uncommon for me to see 9-10 average. Empty I typically see 17-18.

I know people talk about "fake" numbers from chipped rigs, I can't say because I never hand calculated. What I can say is doing the same trips under the same conditions I can not go as far before needing to fuel. While aux fuel tanks are handy I never really considered one in the old truck. I have one in the new truck and it is very nice.
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Old 06-19-2017, 03:15 PM   #7
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I have a 2007 (1/2) 6.6 Duramax with 5" straight exhaust, and mini max chip. I had to replace two injectors at two different times; #3 at 220,000 miles, and #6 at about 260,000 miles. Right now I have 298,000 miles on the truck and plan to buy another new one once this one hits 400,000 miles.

As fas as faux mileage, the computer read outs are only as good as the information received. If the tire size is not adjusted to the actual tire size then there is going to be a poor read out.
Chevy 2500HD 6.6 2007, Bay Hill 320RS 2015
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Old 06-22-2017, 07:40 PM   #8
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The lbz is a very good dmax. Injector problem was worked out by then plus no emission junk that is on the later ones. I have an lmm with 165k on it with no problems. At my age I'm keeping this one.
2008 GMC Duramax 3500HD CC,LB,DRW With some hidin power mods 2007 Mobile Suites 36 SB3
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Old 07-16-2017, 04:24 PM   #9
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I've had my 2007 lbz a number of years and the only non-elective surgery was the crank timing sensor that happened recently. I did do a preventive fix for the transfer case rub issue that's prevalent in these earlier models.
Regarding the computer mileage readout, I actually get about a mile and a half better than the readout shows, currently a shade over or under 20 with me,wife, a couple of medium size dogs, and 100 lbs of tools and stuff in the tool box, and about 11-12 towing just under 12,000. (if I drive it right)
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Old 07-22-2017, 12:41 PM   #10
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I've owned my 06 LBZ since new and absolutely love it. have 138k miles on it now. other than an EGR valve, glow plugs and a couple random things, its been an absolute peach. up until the end of last year, it regularly towed my 15-18Klbs 5th wheel toy hauler for 10 years without issue. sold the hauler and picked up an 08 super c moho with the LMM in it (07 chassis). the LBZ in my truck is rated at 360/650 hp/tq, the LMM in the moho i believe is 330/610 hp/tq. the moho cruises along like no big deal, haven't yet had it on enough of a drive to check mileage or have towed a trailer but overall pretty happy with it. seems a touch quieter running than my truck, but that could be just me. the DPF re-gens about every 220 miles so far and i haven't noticed any power loss while it is going on, but I'm sure the mileage drops.

driving my LBZ then hopping into my buddy's 02 LB7 is an interesting sensation. my throttle response is super lazy compared to his truck. his is very eager to go, mine is a bit more simmered down. the lower compression ratio in the LBZ I'm sure plays a role in that
John & Gina
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Old 08-02-2017, 07:44 AM   #11
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HI, My 03 has 160,000 and I have done injectors once at about 110000. Finally found a mechanic I trust and he changes the fuel filter every other oil change. Says that will help with the injector issue. I wouldn't mind a new truck, but I have 60000 reasons to keep this one a while longer. Does everything I ever asked it to and I get a solid 10mpg towing. At this point in its lide, it rarely travels without a trailer so I don't have an empty mpg, but when it was younger, it was around 15-16.
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Old 08-02-2017, 07:32 PM   #12
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Hi, I also have a 2003 Chevy Duramax LB7 which I purchased new in October 2002. Currently on my 3rd set of injectors. First set started smoking at hot idle about 82Kmi and the second set did the same at 122Kmi. In the first year I added a 30micon fuel filter with a lift pump near the tank and a 2 micron Kennedy Mega after the OEM Fuel Filter and always used Stanadyne Performance Formula at every fill-up so fuel quality was not an issue. Other than Injectors it's been an awesome truck I love to drive. It's had an easy life with no towing until this past May when we acquired a 2011 Cougar 27RKS and the old truck pulls it just great. A newer truck with the added power and 6 Speed Allison would be nice but this one is free and clear and still looks like the day it rolled out of the dealers lot. If a low mileage LBZ were available it would be a good choice. The LBZ has a good reputation. It comes with the 6 speed Allison and doesn't have the DPF or DEF emissions controls. IMHO you can't go wrong with any of the the Duramax versions.
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Old 10-25-2017, 08:58 AM   #13
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I have a 06 LBZ Duramax with 310,000 miles of heavy towing that I have owned since 09/70,000 miles. The only issue was a turbo replacement due to stuck vanes. I have since done the PVC and EGR/fingerstick block to keep the turbo cleaner. Otherwise the truck has performed flawless, getting 21mpg empty and 11.5mpg towing 17k fifth wheel or hot shot trailer w/20k steel coils. I am thinking about a newer Duramax, but this one is running so good.
Rotella synthetic 5W40 every 5k miles, fuel filter every 10k.
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Old 11-11-2017, 07:14 PM   #14
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06 2WD 6.6L LBZ here. 190,000 miles, the vast majority dragging a 13,000 5er. Oil change every 3000 miles. Goes to the local shop once a year & the mechanic is basically told to 'go at it'. If in doubt, change it out. Average maintenance cost has been stable at about $2,500 PA plus oil changes.

From MD the truck has been to Alaska 3 times, to the West Coast 3 times, to Colorado at least 4 times, to Newfoundland 1 time, to Nova Scotia 3 times, all around the mid Atlantic don't know how much. It is like the energizer bunny. The only time that the engine has failed was due to bad fuel picked up in Amarillo, TX.

It has had one radiator replacement. All other parts replacement have been things like suspension & steering bushings plus a few seals.

Gotta love that Isuzu engine.

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