What problems does the LB7 have?

The LB7 injectors had two potential design flaws that could cause injector failure. The first has to do with the internal ball seat inside the injector which would erode and deteriorate from normal wear and tear which would then cause the injector to leak. Secondly, the injector itself was prone to cracking.

Why does my 04 LB7 engine not start?

Now engine wont start anymore. Went to start my 04 LB7 this morning to let it warm up before going to work. As I shut the door and walk away, the engine died. I tried to fire it back up but it just spins over and doesnt start. The truck has 144k, has about 3.5k on new injectors installed by dealer, fuel filter was replaced around the same time.

How big is the tank on a LB7 truck?

The truck has 144k, has about 3.5k on new injectors installed by dealer, fuel filter was replaced around the same time. Truck has about 3/4 tank. No check engine light.

Do you need a rebuild kit for a LB7?

Just as fair warning if its an lb7 make sure your sitting down when you price one! Rebuild kit doesn’t have the valves in it. Usually the valve flapper gets folded or gets some junk in it and doesn’t need replacement.

Are there any problems with the LB7 engine?

Where the LB7 loses reliability is under additional power. The crankshaft and rods are problem areas under serious power. Additionally, fueling and cooling will become a common failure point as well along with the Allison 1000 transmission. Overall, the LB7 is a strong contender for older diesel engines.

When did the Duramax LB7 diesel engine come out?

By the end of its production in 2004, the LB7 got a sizeable power increase to 300hp and 520lb-ft. of torque. Given the age of these engines today, the LB7’s are popular amongst diesel seekers who are looking for a healthy balance of price and reliability.

What causes a fuel line to leak on a LB7?

As part of the fueling system you have a fuel filter and filter head which filters fuel before the fuel is sent through the lines to the injectors. On the LB7, the fuel lines are occasionally known for leaking. However, the majority of LB7 fuel leaks are caused by the filter housing. The head of the housing uses multiples o-rings to seal the pump.

What causes a fuel injector to fail on a LB7?

Aside from the carbon buildup caused by DI, the fuel injectors themselves are also very common failure points, even on non-GM engines. The LB7 injectors had two potential design flaws that could cause injector failure.