Duramax LB7

[cork]

Looking at an older, 2003 GMC 2500. It has 63,000 miles on it and appears to be in good condition.
I know the LB7 is prone to injector failures, anyone have any personal experience? I know the LBZ is probably a better choice but clean low mileage trucks are $$$

 

[hungerbuhler1]

I ran one to 190k miles with no issues. Had to do 2 batteries somewhere around 140k and did brakes around 160k. Good motor.

 

[Chuck Leeper]

Expensive?? Yep! I know more than 1 that got a bill in the neighborhood of $5500 for the swap out at a GM dlr.
My 01 was covered by the extended warranty they sent out: 7yrs/200K miles.

 

[SloGN]

look at the LLY durmax trucks they are 04-early 06 trucks.

 

[87-WE2]

I own an 04 gmc with the LB7 (bought in Nov 03 when the early 04's had the LLY as a snowplow option. In early 04, they discontinued the LB7.) After 140k miles, its time fr me to do the injectors. If you buy an LB7, the single most important thing that can be done to preserve the proper performance of the injectors is to CHANGE THE FUEL FILTER.....often!!! I didn't know this early on and changed at factory recommended intervals and always wondered what all those black specks were in the filter when i emptied it. It was rust from inside the filter. I have had several professional diesel mechanics tell me this personally. The fault is not with the injectors, but with the filtration system. And do not skimp on filters - buy Wix only (or Napa Gold that is made by Wix). The LB7 is a great motor - much more power than most need and probably more importantly, fuel efficient. It was not uncommon for me to average 20mpg (bed loaded) on the highway. My new LMM only gets 16 on its BEST day.

Be careful with the early models' instrument cluster though. I believe in 03 they came out with a "new" cluster that had the Driver Information Center cluster. These clusters were prone to failure of the tachometer, fuel gauge, and coolant temperature gauge. The factory issued a TSB on it but not a recall. If memory serves, GM would replace the cluster if less than 70k miles. After that, the owner was on his own. Mine was replaced by the dealer, and they programmed the correct mileage in the new odometer. If one were to replace his own cluster, they may not necessarily have it re-programmed to read correctly. I'm not saying that this one's odometer is wrong, but 60k in almost 10 years would be extrememly low mileage. Knowing what I know about the cluster issue would lead me to be suspect.

Goid luck with your truck search. The LB7 is a fantastic motor and pulls like a government mule. I have refused a couple of recent offers for mine at $12k. It is worth more than that to me.

 

[87-WE2]

Oh yeah, if it's 4wd like mine is, plan on replacing the front bearing assemblies about every 50-60k miles. They are sealed units and not serviceable. if i remember right they cost about $250, but i can't remember if that's each, or a pair. It's been about 4 years since my last set and i'm due, but they're not terrible yet. They are not hard to do as long as you have a 35mm socket and about an 8-foot cheater!!!! They are SERIOUSLY torqued.

 

[Chuck Leeper]

The early engines weren't designed to use low sulphur diesel, either. I used some Siloo additive to help w/ lubing the system, frequent filter changes. I also had an aux filter on it.

 

[cork]

Thanks to all for the input, 87-WE2 glad to hear you made it to 140,00 on your injectors. I have been reading various Diesel forums and read so many stories about the injectors, but Im sure for every complaint I read there are countless others who have not had any injector problems.

 

[forcefed3.8's]

I had to do injectors on my 03 at 50,000 miles, a friend of mine had to do them at 43,000 miles. We both changed fuel filters with the GM filters every 3 to 5000 miles because we noticed the rail pressure dropping on high hp tunes when the filters started to get dirty. I had an 01 with 81,000 miles on it when I traded it in, original injectors, and my dad had an 02 with 75,000 miles on it, original injectors, and he changed the filter twice.

 

[cork]

I had to do injectors on my 03 at 50,000 miles, a friend of mine had to do them at 43,000 miles. We both changed fuel filters with the GM filters every 3 to 5000 miles because we noticed the rail pressure dropping on high hp tunes when the filters started to get dirty. I had an 01 with 81,000 miles on it when I traded it in, original injectors, and my dad had an 02 with 75,000 miles on it, original injectors, and he changed the filter twice.

Thanks forcefed3.8, I think I will wait unitl I find an LLY or LBZ. Seems some guys get lucky with the LB7 and others have failures with less than 50,000 miles.

 

[cork]

I found and purchased a low mileage LBZ

 

[forcefed3.8's]

Very nice.

 

[SloGN]

sweet!

 

[TT/Ameasap]

My 06 LBZ is for sale in the non buick for sale section. Good truck.