Volume 1 Issue 2 - Duramax Issues and Answers

I would like to know any info about the LB7 injectors. Supposedly redesigned; but all replacements are remanufactures, so what changed?

Response

As technicians, we have been provided limited information as to what specifically was done to the injectors. Officially, we have been told that there have been improvements in the materials used in the injectors. This has been done at least twice, and we have had service bulletins to remind us to use the newer part number of injector. Unofficially, I have been told that the injector ball and seat materials were changed, more specifically the seat itself. Additionally, I have been told that a new surface treatment has been applied to the rest of the internal components to reduce the chance of corrosion due to water. Changes were also made to prevent the injector body from cracking and leaking fuel into the crankcase.

What surprises me is the myth that the injectors have never been redesigned. Many cite the fact that replacement injectors are rebuilt units, not newly manufactured. However, GM is in fact supplying at least the third redesign of these injectors. So why are the injectors rebuilds?

With any new product, the first replacement parts that are available are new units. As parts are installed and cores become available, they can begin the process of remanufacture. This applies to new engines and new transmissions as well. The first Duramax engines we replaced were new off the assembly line. The first Allison transmissions were the same. Now, a few years later, we primarily get rebuilt engines and transmissions. The same holds true with fuel injectors. As regards the quality of the rebuilt units, there is no need to be concerned. They are not rebuilt by a “fly-by-night” operation, but by a manufacturing process unto itself. It’s convenient (yes, and cheaper) to be able to reuse some of the components.

Most of the injectors I have replaced have been new units. It’s only been in the last three years or so that the rebuilt injectors have saturated the supply. Not to contradict myself, but we did have quality control issues with some of the rebuilt units. These problems usually showed up the moment we started the engine. But that was quickly rectified, as GM hates paying for a job twice! Keep in mind that GM has to warranty their own parts, and they despise loosing money.

Many people are very upset about the whole injector issue. Some have even set up class-action lawsuits over this problem. To me, it’s just another one of the glitches that are par for the course on any new product. I’ve seen this kind of thing too often and too long to get overly worked up about it. Yes, I know that many times the customer ends up paying for it.

But in my opinion, GM is far ahead of – not only the 6.5 diesel but also – the other manufacturers in terms of quality and reliability. Really, GM has done the right thing by setting up a special policy to replace the injectors far beyond the normal warranty. They also did a very smart thing by giving all Duramax owners a free fuel filter (the updated dual-element one of course) as that was really a major part of the injector failure equation.

And now I’ll get off the soapbox.

Joel Paynton

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