Last Updated: 10.12.2020

Hi all, today we had a hard time because we were asked to review the best injectors for LB7 Duramax, and honestly, there isn’t much leeway with this issue. There is one leading injector fabricator for this application, and that is Bosch.


The 5 Best Injectors for LB7 Duramax:

    1. Bosch Automotive LB7 Replacement Injector – the best injectors for LB7 Duramax
    2. Dieselogic Duramax LB7 Diesel Injector Single
    3. Dieselogic 2001-2004 CHEVY/GMC DURAMAX LB7 6.6L DIESEL INJECTOR LB7 SET
    4. Dynomite Diesel Products Injectors Duramax 01-04 Lb7 Injector Set – 50Hp – DDP LB7-50
    5. Set of 8 OEM GENUINE Refurbished LB7 6.6L V8 Diesel Injectors for Chevrolet Silverado 2500 HD/3500, 01-04 GMC 2500 HD/3500, 01-04 GMC Sierra 2500 HD/3500

Top-Rated Injectors for LB7 Duramax List:

Product namePhotoFeatureProsView on Amazon
1. Bosch Automotive LB7 Replacement Injector 1. Bosch Automotive LB7 Replacement InjectorRemanufactured injector (Bosch OEM base)

  • Doesn’t cost a lot

  • Backed with a warranty

More Information
2. Dieselogic Duramax LB7 Diesel Injector Single 2. Dieselogic Duramax LB7 Diesel Injector SingleBrand-new injector from Bosch, made to OEM specifications

  • Brand-new, so gives the engine a new lease of life

  • Comes with the new-style body (so no cracking like the original)

More Information

  • remanufactured and calibrated

  • original cores

More Information
4. Dynomite Diesel Products Injectors4. Dynomite Diesel Products Injectors Duramax 01-04 Lb7 Injector Set - 50Hp - DDP LB7-50This is the Duramax 01-04 LB7 BRAND NEW Injector SET – 50HP

  • comes with no core charge

  • new configurations

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5. Set of 8 OEM GENUINE Refurbished LB7 6.6L5. Set of 8 OEM GENUINE Refurbished LB7 6.6L V8 Diesel Injectors for Chevrolet Silverado 2500 HD/3500, 01-04 GMC 2500 HD/3500, 01-04 GMC Sierra 2500 HD/3500This is the Refurbished LB7 6.6L Bosch refurbished

  • with direct injection

  • removed en-block

More Information


All the information and opinions you find on come from a team of automotive journalists and an independent mechanic, Steve “Whip” Whipple with 11 years of auto industry experience. We look at the latest market research, talk to experts, and draw from our own practical experience to bring you reviews and guides that reflect what you’ll encounter in your garage. For more information about the team, see here.

So, what we did was look at all the alternatives of a Bosch fuel injector, including new, refurbished and remanufactured. Guess what, there is a lot of stuff going on in the world, and there is a large selection that can make you take a bad decision.

Just a quick note on the differences between the types of injectors you will find.

Refurbished injectors are usually the cheapest option to buy. Refurbished means that the injector is used, and was removed from an engine, and was completely cleaned and tested for any integral damage, as well as meeting OEM performance requirements.

Remanufactured injectors are parts that were used in an engine, but when removed were stripped down to their core elements rebuilt. The damaged parts were replaced with new parts, and as such, remanufactured injectors are more expensive than refurbished. They are also tested for OEM compliance.

OEM Rebuilt injectors a are parts that have been used and stripped down like a remanufactured part, but all the components apart from the body have been replaced with new ones. These are as close to a new stock injector as the original and are the most expensive of the re-injector category.

New injectors are obviously new from the manufacturer, and their price depends on the brand and type you decide to purchase.

In the end, we managed to create a nice tidy list of the top 4 best injectors of the LB7 Duramax and hope you will choose any one of these for your application.

Best Injectors for LB7 Duramax Reviews:

1. Bosch Automotive LB7 Replacement Injector – the best injector for LB7 Duramax

No products found.

For a lot of truck owners, it makes more sense to get a brand-new replacement injector and the Bosch Automotive LB7 Replacement Injector is the ideal choice in that regard. This is because, while slightly more expensive than a remanufactured/refurbished part, it’s a brand-new product. That means a higher peace of mind; no need to send the core for a refund. And since you’re installing an OEM product, you can be sure that it’ll work optimally. 

It’s made for the LB7 Duramax trucks made with the model years 2001 – 2004.5. Bosch makes the injector with factory specs and it replaces the product 0986435502. Sold individually, this injector is confirmed to be updated with a new body (that resolves the cracking issue prevalent on early injectors) and a hardened chrome-plated ball seat.

While the listing mentions that the required O-rings and copper crush washers are included in the package, you should confirm it with the seller before making the purchase. The listing also doesn’t include information about the warranty; Bosch indicates an unlimited mileage warranty for 12 months.


2. Dieselogic Duramax LB7 Diesel Injector Single

No products found.

This individual Dieselogic injector is a remanufactured item, made with the Bosch OEM part as the base, and with all of its faulty/worn out parts replaced by new ones. This means while not entirely new, the injector comes with new parts, is backed by a warranty, and most importantly, doesn’t cost much.

The injector boasts precision-drilled spray holes, thoroughly tested injector body, and new chrome-plated ball and micro-finished seat for control valves. The O-rings and copper crush washers come pre-installed as well.

Compatible with the Duramax GMC/Chevrolet trucks made with the model years 2001 – 2004, this injector is covered under a 1-year unlimited mileage warranty. Dieselogic will buy your truck’s current injector core and offer a predefined refund to you as well, assuming that the core meets their condition requirements.


  • We will buy back your Core, Core must meet Core Policy and Timeline
  • CORE POLICY: All cores must be “cosmetically” in original condition i.e. no damage to the external body We will not be responsible for any damage caused in transit The following will result in partial core credit or denial: Cores not being “like for like” (same injector as you are purchasing), Broken/missing solenoid, dividers Broken/missing electrical connecting studs, Core tampering or suspected disassembly, Missing/damaged nozzles, Missing internal components, Missing external components.
  • For Cores that meet Core Policy and are returned within 30 days of ship date >> Refund of $50.00/EA
  • For Cores that meet Core Policy and are returned within 31~60 days of ship date >> Refund of $37.50 /EA
  • For Cores that meet Core Policy and are returned after 60 days of ship date >> Please contact us for Refund, amount varies based on wholesale market value

The LB7 range is remanufactured and calibrated for perfect performance. These original injectors are all original Bosch with original cores and are as exact to the OEM standard as you will get. This set of 8 comes with O-rings and copper crush washers. The Dieselogic remanufactured injector body is tested for its original integrity, and the pintle nozzle and needle valve are replaced. The leak offline is usually cleaned out thoroughly. Rather than check the springs integrity, they are replaced with a new one.

4. Dynomite Diesel Products Injectors Duramax 01-04 Lb7 Injector Set – 50Hp – DDP LB7-50


The DDP LB7-XX High Flow Injectors for your 01-04 GM 6.6L Duramax LB7 will make your Duramax Fly. With the Allison 5 and 6 speed, the Duramax is already fun to drive. Why not add an addition kick with DDP Injectors. Unlike an electronic box, honed performance injectors are almost impossible for a factory technician to detect. With DDPs Balance Honed injectors you can be confident that your warranty will not be compromised and youll have the extra pulling power to beat your friends up the mountain. The 50 horsepower nozzles will give you 50hp at the wheels. You can use these in conjunction with an aftermarket electronic box or downloader without the worry of draining the fuel rail dry. We do not offer a 90hp version because we feel that 50 is the largest you can do without needing dual injection pumps. These injectors work equally well in a completely stock truck.

This set comes with no core charge and provides around 50 RWHP over stock. Since this is a new set, it comes with the new configurations that match all models from 2001 and upwards.

5. Set of 8 OEM GENUINE Refurbished LB7 6.6L V8 Diesel Injectors for Chevrolet Silverado 2500 HD/3500, 01-04 GMC 2500 HD/3500, 01-04 GMC Sierra 2500 HD/3500

These are refurbished Bosch injectors #0986435502, they work with direct injection OE type engines and are a perfect replacement part. In many instances, all the injectors are removed en-block from an engine together with the damaged parts, and as such, are basically as good as new. These are only washed and cleaned and tested for compliance with OEM standards,


What is the best injector for LB7 Duramax?

Choosing an injector for the LB7 Duramax is a pretty straightforward thing. The ideal choice is always going to be an OEM-spec brand-new unit. That gives you unrivaled peace of mind, although these are slightly more expensive than the remanufactured ones. Our choice for the Best Injectors for LB7 Duramax has to be the Bosch Automotive LB7 Replacement Injector.

If you’re looking at saving some money but don’t want to compromise on the quality, then the Dieselogic Duramax LB7 Diesel Injector is an interesting product. It’s based on the Bosch OEM injector, has new components, and is backed by a warranty as well. You can also get a set of eight for these (Dieselogic Duramax Set of Eight). The Dynomite Diesel Injectors, on the other hand, promises to offer improved power (up to 50 rwhp) and is said to match trucks made in 2001 and beyond. Another cost-effective choice includes the Refurbished Bosch injectors. Keep in mind that it might be tested to OEM standards but will not match a brand-new or remanufactured product.


The 6.6L Duramax engine was released back in 2001, and this engine is considered to be a pinnacle of diesel performance. The fact that the engine has not been unchanged only had a few upgrades made to its design is a testament to this amazing feat of engineering.

Injector issues can lead to catastrophic engine problems if not diagnosed early and treated. During 2001 and 2004 the Duramax injector design was problematic, and there were many failures leading the company to redesign the original injectors from scratch.

Since GM managed to make changes after 2004, a lot of vehicles from 2001 to 2004 remained an issue, and there are many motors still running on the old problematic injectors. What I suggest is that when you buy a 2001 to 2004 model, you check if it has the original injectors, if this is the case, you want to replace all of them immediately.

One of the issues with the earlier models included a harness chafe of the wiring. This means that you need to replace the harness as well as the injectors.

If you are an experienced mechanic or a 6.6L Duramax enthusiast then you can most probably diagnose the issues yourself, if not, here is a list of the crucial Duramax replacement issues to deal with.

Main points for 6.6l Duramax replacement issues

      1. Find the drain valve and draining the coolant. Remove the coolant since it will flood the combustion chamber when you remove the injectors. Don’t forget to disconnect the battery when draining your coolant.
      2. Remove the neck of the coolant, the A/C condenser and the water thermostat. You might consider replacing your water thermostat too.
      3. Remove the fuel injection control module and remove the fuel injector keys.
      4. Remove the glow plug harness
      5. Cut and remove the fuel lines with the appropriate tool, and make sure to drain the line.
      6. Remove the valve cover, and then remove the fuel return lines.
      7. Using the appropriate tool, release the bolt from the injector hold down.
      8. Now pry the hold down pen with a prying bar and remove the injector cup.
      9. Now you can install the new injector.


What goes wrong with LB7 injectors?
Every working part in a truck wears as it’s used over and over again. Injectors aren’t any different. But the fairly well-known issue about LB7 injectors is that during the 2001 – 2004 period, the injectors weren’t the strongest. The injectors used to fail frequently, which prompted GM to redesign the injectors and extend the warranty. The faulty injectors can, in turn, affect the overall functioning of the engine and reduce the life of other components. One issue is that bad injectors spray a lot of fuel into the engine, even when there’s no requirement.
How much does it take to replace injectors on a Duramax?
The Duramax is an 8-cylinder engine. This means there are eight injectors in total. So if you’re looking at a stock injector replacement (like the Bosch Automotive LB7 Replacement Injector), you can easily spend close to $2000+ for a set. While you might be able to replace the injectors all by yourself (if you’re mechanically inclined and follow the instructions closely; take a look below to get an idea), a visit to the mechanic will add some labor cost, making replacing the injectors a little heavier on the wallet.
How long do Duramax injectors last?
Under normal circumstances, the current injectors are bound to last a while — at least the 200,000 miles they get coverage for from GM. The earlier problematic injectors did have a tendency to go bad sooner. Users reported failures even before the truck would hit the hundred thousand mark, which caused GM to make changes to the design and to extend the warranty.

How to change injectors on 6.6 Duramax LB7?

Tools Needed:

      • Basic tools
      • Wrench kit

Materials Needed:

      • Injectors x8
      • O-rings and washers (16 and 8) if the injectors don’t include these)
      • Installation kit
      • Sealant

Step 1

Figuring out if the injectors are the issue

Replacing the injectors is a fairly long process, but it’s also straightforward. But before embarking on the journey, you need to figure out if the injectors are problematic. You can consult the local mechanic to check for the telltale signs. Or if that doesn’t work out, they can check the balance rates to figure out the health of the injectors.

Step 2

Disconnect everything

Empty the coolant

The first thing to do before replacing the injectors is to empty the coolant through the drain hole. This will ensure the combustion chamber doesn’t get filled with coolant.

Disconnect the battery and control modules

To ensure there’s no power in the system, it’s a good practice to remove the battery’s connections. While at it, you should also disconnect the fuel injector control module. This is so it won’t suffer any possible damage while removing the injectors.

Don’t forget the other bits

There are other connections that are recommended to be removed before you access the injectors. Some of these include the AC, the thermostat, and the neck of the coolant. Following that, the fuel lines need to be disconnected from the injectors — and the same applies to the electric wiring. Similarly, the glow plug wires need to be disconnected and removed.

The removal until this step is different on the driver’s side compared to the passenger’s side. Keep in mind that it’s best to refer to the user manual and double-check with an expert if you’re unsure. In addition to the removal of the parts/connectors, for the driver’s side, you might also be looking at disconnecting the radiator hose, main engine wiring connectors, glow plug module, etc.

Step 3

Extracting the injectors

Wrench it out

The injector lines will require the use of a wrench. Take these out, remove the upper valve cover, followed by the lower valve cover. This might need some effort but at the same time, care has to be taken, as only some of the bolts need to be removed. The injector return line needs to be removed after this.

Final extraction

Unscrew the injectors out carefully from the bracket they’re mounted on. Now there are a few things to keep in mind as you pry these out. First, the copper washer needs to be removed. The cup can be reinstalled but you’ll need new O-rings when it’s time to put everything back in place. You’ll run a risk of introducing the coolant into the combustion chamber as you remove the injector. This is why it’s extremely important that you drain the coolant earlier.

Step 4

Putting the new injectors in

Install the injector

Mount the O-ring onto the injector and install the copper washer at the bottom of the injector cup before going ahead with the installation. Refer to the user manual for the correct amount of torque. The injector goes into the clamp and you must secure it by applying the said amount of torque.

Reverse the procedure

Start with the return lines, apply a new sealant, and bolt it down. Then you move on to the lower valve cover, install the injector harness and bracket, and reassemble the upper valve cover. The correct bolts need to be applied — and new sealant as well, where applicable. Put the injector lines in place, and don’t forget to seal the top as well.

Step 5

Final connections


Reconnect and assemble everything as before, including the fuel injector control module and the battery. Get the engine ready for a start-up, but don’t forget to refill the radiator with coolant. Recheck the connections. And you’re ready to go.

Bonus: How to clean an injector

Fuel filter basket:  This is washed and tested to make sure no debris remains to clog the pintle and seat.

The EFI (Electric Fuel Injector) is calibrated using the ODBII ECU after cleaning to reach the optimum permeance indicators required by OEM specifications.

Return Spring: This washed in a solution and then tested for integrity and tensile strength.

Pintle: This micromachined part is replaced in most cases, but in the refurbished models is cleaned in a solution and tested for micromovement versatility.

Pintle seat and cap: The seat and cap determine the spray pattern and flow rate of the diesel and as such, need to be cleaned in a solution and reset in a precise manner. The O-ring is used to insulate the seat form the heat of the engine.