Chevy LS4 Engine Problems – The Impala SS Monster Engine!

Chevy LS4 Engine Problems – The Impala SS Monster Engine!

December 20, 2023 0 By CarGuy

Are you looking to get an Impala SS with the LS4 engine and you want to learn more about the Chevy LS4 engine problems? If that’s correct, you are in the right place because, in this article, there will be a lot to cover.

Doing your own research is key when it comes to buying a used vehicle. You need to learn what kind of problems a car is hiding for you. You just have to know all of the possibilities that you can come against. And persistence is the key for you to get a nice car and not a pile of problems that will ruin you mentally and emotionally. And that’s why we are here to help you out.

First, we are going to learn more about the specs and applications of the LS4 engine, then we are going to cover the Chevy LS4 engine problems and learn what troubles this engine the most. Lastly, we will give it a reliability score. So, let’s get started!

Chevy LS4 Engine Specs

The Chevy LS4 is an engine that belongs in the Gen IV Chevy small block engine lineup. This engine shares a lot with the 5.3 Vortec that we covered previously. But this is not a truck engine. The LS4 is a proper high-performance V8 engine.

This LS4 engine is somewhat of an exotic engine because these engines were only used in a few models and these were produced in limited numbers.

So, the models that have the LS4 engine cost quite a lot on the used market, especially if you find an Impala SS in mint condition.

The block of the LS4 is aluminum, just like the cylinder heads. What is interesting about the engine is that it was adapted for front-wheel drive cars. So, it was transversely mounted. These engines have a different bolt pattern for the bell housing.

Other differences also can be noted. Front-wheel-drive LS4 engines have shortened crankshaft, the water pump is mounted to a different spot, and revised oil pan baffles. AFM is also included in this engine.

But here are the most important specs of the LS4 engine.

  • Configuration: V-engine
  • Number Of Cylinders: 8
  • Displacement: 5.3L
  • Bore: 96 mm
  • Stroke: 92 mm
  • Block & Head Material: Aluminum
  • Head Design: OHV, 2 valves per cylinder
  • Compression Ratio: 10:1
  • Horsepower: 303 hp
  • Torque: 323 lb-ft

Chevy LS4 Engine Applications

Now let’s list the applications of the LS4 engine.

  • 2006 – 2009 Chevy Impala SS
  • 2006 – 2007 Chevy Monte Carlo SS
  • 2005 – 2008 Pontiac Grand Prix GXP
  • 2008 – 2009 Buick LaCrosse Super

Chevy LS4 Engine Problems

Now let’s find out the most common Chevy LS4 engine problems.

  • Engine Misfires
  • Lifter Noise
  • Oil Consumption
  • Intake Manifold Leaks

We listed the common Chevy LS4 engine problems, now let’s move on and further elaborate on these problems in detail.

We feel the need to further explain these issues and learn more about the circumstances of when and how they appear, as well as how serious these problems are. So, if you think that you need to learn more about the details, follow along because there will be a lot to cover.

1. Engine Misfires

The first problem on our list of problems with the Chevy LS4 engine is the problem with engine misfires. So, what are engine misfires?

Well, engine misfires are basically uneven explosions that occur in the cylinder. They can be caused by a number of issues but this time they are triggered by bad spark plugs.

These engines have a problem when the spark plug electrodes get dirty with soot and this prevents the operation of the spark plugs.

So, whenever this is the case the engine could end up misfiring. This problem has a simple solution and that is replacing the spark plugs.

Usually, a brand new set of spark plugs fixes these issues. Spark plugs are also pretty cheap and cost less than $10 apiece.

Other symptoms associated with this problem include check engine light, rough engine idle, poor engine work, and poor fuel economy.

Now let’s move on to the next Chevy LS4 engine problems.

2. Lifter Noise

Lifter noise is also a common problem on these engines. So, what is lifter noise, and why does it happen?

Well, lifter noise is produced by the lifters, these are components that are in contact with the camshaft.

On many of these newer LS engines equipped with Active Fuel Management (AFM), these lifters start to rattle and fail.

This AFM system is there for the purpose of shutting off four of the cylinders when the engine is not under load to improve the fuel economy.

And the lifters for this system are known to be very unreliable. This is a common problem on many LS engines as we noted.

The solution is to replace the lifters with new ones when the rattle starts to occur. This is the only way around the problem.

Also, many owners simply delete this system and solve these problems permanently on their engines.

3. Oil Consumption

Oil consumption is another very common problem that is also triggered by the AFM system. Since these engines were not susceptible to oil consumption before they decided to add this system.

So, these LS4, along with other engines that use AFM tend to consume more oil compared to the older versions of the LS.

There were some revisions done by Chevy in the newer engines where they added some shielding and deflectors to prevent this from happening but this still happens.

This oil consumption can also damage the spark plugs since when oil gets ignited there is soot that is created on the valves and also this soot covers the electrodes of the spark plugs in the process.

4. Intake Manifold Leaks

The last problem on our list is the intake manifold leaks. These leaks are very common on all of the LS engines.

What happens is that the intake manifold gasket fails over long use and abuse and allows vacuum leaks to occur in the engine.

These vacuum leaks will allow unmetered air to enter the engine and this will completely ruin the work of the engine.

The engine’s air-to-fuel mixture will be completely off and will run very poorly. There will also be check engine light, misfires, rough engine work, engine stalling, surging, etc.

The solution to this problem is to replace this gasket with a new one and this will solve the problem permanently.

You just need to remove the manifold and install the new gaskets. For a person who is into mechanics, this is a very simple job that can be done in a few hours.

Chevy LS4 Engine Reliability

The reliability of the LS4 is very strong, and this is mainly due to the fact that this is a 5.3 Chevy. There are no crazy modifications in this engine like the ones you can find in the LS1, LS6, or LS7 engines.

The engine also makes modest horsepower which doesn’t strain the components and it has good longevity because of this.

So, if you can find one of these samples in good condition, you will not regret if you purchased one besides the modest numbers that the engine is making.


In this article, we have covered quite a bit when it comes to the Chevy LS4 engine. First, we learned more about the specs and applications of the LS4 engine.

In the second part of this article, we learned more about the Chevy LS4 engine problems and reliability. Overall, this is a really good and reliable engine.


What Are The Common Chevy LS4 Engine Problems?

This engine does not have serious problems, there can be issues with spark plugs, vacuum leaks from the intake manifold, and issues with the AFM system represented in lifter tick and oil consumption. But besides that, this is a pretty bulletproof engine.

Is The Chevy LS4 Engine Reliable?

Yes, this is a pretty reliable engine that if you maintain well will run forever. Still, there are some issues though but nothing too significant that will ruin its reliability score.