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LBZ reliability


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I'm looking to buy a older Duramax for hauling and one of the best deals is a 2008 LBZ. I'm reading about the issues online like fuel starvation, aluminum head problems, glow plug problems, harness chaffing, over heating and other issues. And I'm wondering if any guys with an LBZ have had any of these issues. And are there preventative measures to avoid them?

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Tough question to answer.

I don't own a diesel but buying used is always a roll of the dice once they get older.

If you get lucky and find a one owner truck with all the maintenance records that would be great.

Here's an example.

I bought a 2003 ATV.

Ran great for a while.

I have rebuilt the carb.

New front brakes, bearings and seals.

All fluids changed.

It's still going to take some work IMO to get it in tip top shape.

 

:)

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LBZ was only available in 2007 Classic, the GMT800 platform.  My buddy bought one new, has 213K and has had no issues with it at all.  He marvels that he's had to do nothing to the motor other than fluid and filter changes after all these years.

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Without double checking, I believe the 2008 was the LMM, not the LBZ. You wanna stay away from that, they were the first duramaxs equipped with a DPF, which is the big bad guy in diesel emission controls. Also GM went bankrupt around that time, so they cheaped out on a lot of stuff.

 

The LBZ was 06 & 07. The later 07 model LBZs are good motors. The older LB7s and LLYs aren't so good, the LB7s are known to go through injectors and the LLYs are known to go through head gaskets.

 

 

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Yeah, I was at work on my phone when I posted this, this morning. The first web site I went to after typing in "2008 Duramax specs", said LBZ so I ran with it. The more I've looked at trucks through out the day, the more I'm leaning towards a Cummins or a 06-07 GM. I just have no desire to get back into the GMT900's and their sub par interiors. I'm going to look at a 2010 6.7 Ram 2500 tonight and an 07 LBZ on the weekend. I haven't completely ruled out a 6.4 or 6.7 F250, but Ford has failed me 3 times in a row with their junk. So I'm hesitant. 

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LBZ were the "best of the best" to many and still are, provided you can find a clean and maintained one.  Most powerful ones GM did before all the emission stuff.  They were the only GMT-800 platform to get the upgraded 6 speed Allison (2001-2005 had the 5 speed) as well. 

 

LMM is basically LBZ, and is even more so an LBZ if you delete the DPF and 9th injector. 

 

LLY there is the "icepick" injector harness issue that comes up, and some have the buggy cooling fans that would damn near drop a ton of power and get hot when working hard.  .

 

LB7 love injectors, and are the most difficult of the 6.6 family to change them on.    

 

LB7 to LMM, P0087 comes to mind, especially if its been tuned.  Ends up towards fuel pressure regulators or even injection pumps.  If one fails the pump, every single line past the pump gets changed, and every line before the pump flushed (return style fuel system) to eliminate any potential metal contamination.  Stock trucks seem to do it a lot less frequently.  Lift pump doesn't hurt to add either way you cut that though. 

 

LB7 to LMM, fuel coolers rot out. 

 

LML in the K2 and GMT-900 (2011+up frame) seem to enjoy coolant leaks that go un-visualized because its the head gaskets almost every time.

 

L5P seems good so far.  Jury is still out though. 

Edited by newdude
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The only downside to the L5P so far is that they can't be tuned, and therefore can't be deleted. Also, I'm not super familiar with the Cummins engines, but I am friends with the guys at a local diesel shop and they said the 6.7 cummins are known to blow head gaskets.

They said the 6.7 is basically a bored out 5.9 block, therefore the gap between the cylinders is very small. Even with head studs they like to blow. The heads need to be o ringed and some guys even tap out the block to get thicker head studs in to lock the headgaskets down


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I liked the older interiors but like the GMT900s better.  Nice to know that the LMM is an LBZ without that Obama stuff that killed their mileage.  My buddy's LBZ runs like a top, gets about 19 mpg in town and mid 20s I think he said on the highway.

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1 hour ago, davester said:

That's hilarious.  GM designed, built and sold it before Obama even began running for President.

Well aware of that.  It's the result of Statism and President Obama is the face of it.

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