Looking at getting a Duramax

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
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O/P, your best bet is the LBZ, unless you're prepared for future injector costs (there is no "cure" for them...they'll fail again down the road). I dont believe most people are prepared for that cost.
 

OregonDMAX

NOT IN OREGON, NO DURAMAX
Apr 28, 2013
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O/P, your best bet is the LBZ, unless you're prepared for future injector costs (there is no "cure" for them...they'll fail again down the road). I dont believe most people are prepared for that cost.

Best bet is to not buy a diesel they are all money pits, there isn't one e that isn't going to cost money eventually no matter how you look at it they will all cost thousands eventually.
 

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
15,611
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Mid Michigan
I no longer recommend LB7s to anyone new to diesels, havent for years, unless they are prepared to do any work themselves.

I've said for years that "diesel = gourmet" when it comes to repair work/parts costs.
 

DAVe3283

Heavy & Slow
Sep 3, 2009
3,727
296
83
Boise, ID, USA
I agree with TheBac and OregonDMAX both. You really don't want a diesel if you are trying to save money. They are all money pits (not just GM, any modern diesel from any brand). If you can do your own work, the LB7 will be a great motor, but you will need to do injectors. The later ones don't need as much TLC, but are even more expensive when you do.

Love everyone says the 6 speed is so nice, why does the lb7 with a 5 speed get better mpg than any other dmax out there :thumb:
The 6 speed helps with mileage for sure, just everything newer than a LB7 horks down the fuel. We did a 6-speed conversion on my brother's LB7 Suburban 2500, and that thing gets implausibly good mileage. Consistently 19-20 MPG at 85 MPH!! :eek:
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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Phoenix Az
I agree with TheBac and OregonDMAX both. You really don't want a diesel if you are trying to save money. They are all money pits (not just GM, any modern diesel from any brand). If you can do your own work, the LB7 will be a great motor, but you will need to do injectors. The later ones don't need as much TLC, but are even more expensive when you do.


The 6 speed helps with mileage for sure, just everything newer than a LB7 horks down the fuel. We did a 6-speed conversion on my brother's LB7 Suburban 2500, and that thing gets implausibly good mileage. Consistently 19-20 MPG at 85 MPH!! :eek:

must be the variable vane turbo. i get the same mpg as i did on my LB7 setup.
 

ChrisPerry

...........
Apr 4, 2016
209
6
18
Ventura, CA
My buddy gets about the same mpg as me when we convoy with trailers somewhere, he has a 07 lbz classic on 35's, no egr or cat.

If deleted and tuned the same, I think they all get close to the same mpg.:dontknow:
 

OregonDMAX

NOT IN OREGON, NO DURAMAX
Apr 28, 2013
3,964
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On 265's with good driving habits I always got a consistent 22 mpg hand calculated and it would drop to 18-20 with mixed city and I got a personal best of 25.4 and went over 550 miles on a single tank (short bed) the owners manual says 26gals but I was on e for 35 miles looking for fuel and when I filled it up it took 22.4 gallons and I mean I was on fumes.

The mileage gets worse as motors get newer, it's not just emissions devices affecting fuel mileage, you don't think the turbos, stock tuning, even internals like pistons and heads don't play a roll in controlling emissions and flow characteristics affecting mileage.
 

036.6turbo

Active member
Jan 17, 2014
714
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I no longer recommend LB7s to anyone new to diesels, havent for years, unless they are prepared to do any work themselves.

I've said for years that "diesel = gourmet" when it comes to repair work/parts costs.

The never ending "which engine family is better debate", what the hell, I'll chime in.

I often wonder how many people actually KNOW how long a set of LB7 injectors last, I see a lot of people throwing numbers out there, and in my opinion they exaggerate on the plus side.

My LB7 had 336,000 miles on it when I pulled it out, it was beginning to haze white, I knew it needed it's 5th set of injectors. Sets one through three averaged 70,000 miles per set, set number four went 105,000.

So that's my history with the LB7. So WTF do I know?

Well the other part of the story is the whole 10 year 200,000 mile, special bulletin deal from GM. Way back in the day, over on another web site, my user ID is 94383Z71 (reference to my 1/2 ton, stroker motor folly back in the late 90s), anyhow I was one of the knuckleheads that could run VIN reports through the GM system (still can).

I think my post count over there is close to 10,000. The large majority of those was running VIN history for us LB7 guys, to see if we were in line for a freebie set of injectors from uncle GM. Of all those reports I ran, by and large the average LB7 injector life span was around 70,000 miles. Period.

The LB7 is a solid motor, mine never ceased to amaze me. Even over 300,000 miles, it used no oil, pulled like a freight train and never left me stranded. Having said all that, my 03 now has an LBZ / six speed in it. The LBZ is better, hands down. Pulls harder, runs quieter. It, combined with the six speed Alli, are a much better platform than the LB7. No doubt about it.

As far as mileage goes, to be honest, I never check it, but my frequency of visits to the pump, have not changed dramatically, I can tell you that.

Now on to the LML, I have not towed with mine yet, but I can tell you it is much more refined than the LBZ, I'm looking forward to getting it done and selling the 03. The 15.5 will be deleted with trans safe tunes and driven, a lot.
 

zf>allison

you never had your car.
Apr 30, 2013
3,394
0
36
elsberry mo
I would never buy anything newer than an 06 because they quit putting real transmissions in them in 06:D
Other than that I'd say get you an lly zf6 and you will be set, just ask me I have two of them:thumb:
 

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
15,611
1,868
113
Mid Michigan
The never ending "which engine family is better debate", what the hell, I'll chime in.

I often wonder how many people actually KNOW how long a set of LB7 injectors last, I see a lot of people throwing numbers out there, and in my opinion they exaggerate on the plus side.

My LB7 had 336,000 miles on it when I pulled it out, it was beginning to haze white, I knew it needed it's 5th set of injectors. Sets one through three averaged 70,000 miles per set, set number four went 105,000.

So that's my history with the LB7. So WTF do I know?

Well the other part of the story is the whole 10 year 200,000 mile, special bulletin deal from GM. Way back in the day, over on another web site, my user ID is 94383Z71 (reference to my 1/2 ton, stroker motor folly back in the late 90s), anyhow I was one of the knuckleheads that could run VIN reports through the GM system (still can).

I think my post count over there is close to 10,000. The large majority of those was running VIN history for us LB7 guys, to see if we were in line for a freebie set of injectors from uncle GM. Of all those reports I ran, by and large the average LB7 injector life span was around 70,000 miles. Period.

The LB7 is a solid motor, mine never ceased to amaze me. Even over 300,000 miles, it used no oil, pulled like a freight train and never left me stranded. Having said all that, my 03 now has an LBZ / six speed in it. The LBZ is better, hands down. Pulls harder, runs quieter. It, combined with the six speed Alli, are a much better platform than the LB7. No doubt about it.

As far as mileage goes, to be honest, I never check it, but my frequency of visits to the pump, have not changed dramatically, I can tell you that.

Now on to the LML, I have not towed with mine yet, but I can tell you it is much more refined than the LBZ, I'm looking forward to getting it done and selling the 03. The 15.5 will be deleted with trans safe tunes and driven, a lot.

I dont think you fully understood my post. If someone were to come on here and ask about an LB7 and included "I know about the injector issues and am prepared for them" or "I do all my own work, injectors do not scare me" -- something like that -- then sure, Id recommend the truck.
But neophytes brand new to a Duramax pickup? Oh hell no. Thats completely irresponsible.
More and more, the only people who are joining here are these kinds of people. We cant treat them or our information like we do every other seasoned/experienced Dmax people. They have no idea what to expect, no idea what to budget for. Would I want a surprise $5K bill on a truck I just bought and thought was going to be a decent vehicle? Nope. So I treat others that way, too.

Yep, I remember you from DP.

Compare parts costs for our engines compared to LS's. Huge difference.

My OEM injectors were fine in my truck at 156,000. Balance rates were all good. They'd have gone a lot longer if I didnt hurt the engine and had to pull them during the rebuild. Do I regret that? Yep. But what other choice did I have?
 

2008lmmchopper

New member
May 28, 2017
275
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No love for the lmm's?!
I'm with you on the lmms. I chose an lmm over a lbz. They don't really have many problems and bad problems are rarely heard of. I have had mine over a year now I tow 15k pound fifth wheel every 3-4 weeks all over the northwest. Not an issue.

2008 gmc sierra 2500 lmm
 

2008lmmchopper

New member
May 28, 2017
275
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Lb7 has injector issues yes, but Id rather do injectors on an lb7 than head gaskets in an LLY and lbz has no room to grow into in power imo they all have issues, the lmm has an ass ugly frontend and interior is cheap and the LML you'll end up spending 4g just to make it reliable and emissions free.
Love everyone says the 6 speed is so nice, why does the lb7 with a 5 speed get better mpg than any other dmax out there :thumb:
Damn man lol I got a gmc and I love the front end. My interior isn't cheap I don't think. I mean everything's plastic and fake wood grain but the leather is nice and comfortable I think. To each is there own I guess.

2008 gmc sierra 2500 lmm
 

2008lmmchopper

New member
May 28, 2017
275
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I am on my first duramax so I wouldn't take my word over some of the veterans In here. I will say I know guys who have all the years. From 02 all the way to 2017. Some stock and some modified. Now I think you should do yur homework real hard on it. And then make an educated decision. Don't make one from what others say. If you have it narrowed down which it obviously sounds like you do. I'd then do your homework on both motors. Know everything you can know about them. Find out what the major issues are, what areas need work etc etc that's what I did I ended up buying an 08. It took me 2 months of searching and researching. The lmm is strong, not very many "common" issues actually the least of the duramax motor family, strong injectors and fuel system etc you can find them for great deals low low miles and since everyone thinks the lbzs are the ticket most lmms are not thrashed on. Down side is it cost a lot to get the emissions crap gone. Everyone has an opinion. I just did my homework and chose what I thought would be the best motor, for a good deal, least issues and newest without spending 45k or more. Another big thing to me is buy something that's stock not ****ed with. And if it's got all a lot of records that's good. And southern trucks are a plus stay away from stuff that's been on the coast. Welcome to gm. I've had a slot of diesels ford's and dodges. I'll never go back.

2008 gmc sierra 2500 lmm