6.4 HEMI Problems And Reliability!

6.4 HEMI Problems And Reliability!

April 14, 2023 0 By CarGuy

Are you in the market for a car with a 6.4 HEMI engine and you want to learn more about the 6.4 HEMI engine problems?? Well, if that is the case, you will find this article quite useful!

Doing your own research is always a smart thing to do if you want to get something really reliable. Every car engine has some issues. Some of them are more problematic, while some of them are to a lesser extent. It is your task to gather the right information and make sure that the engine you want to buy is good. And this is why we are here to help you out.

First, we are going to learn the basic specs of this engine, its applications, as well as the 6.4 HEMI engine problems, and its reliability score. So, without further ado, let’s dive in.

Basic Chrysler 6.4 HEMI Specs

The 6.4 HEMI is a third-generation HEMI, this concept was revived by Chrysler in the early 2000s. There were a few engines released on this same architecture. Namely, the 5.7L, 6,1L, 6.2L, and 6.4L. The 6.4L is the engine that we are interested in this article.

This engine is a V8 pushrod engine with 6.4L in displacement and is known simply as the 392. This is because the engine is rated at 392 cubic inches in displacement.

Nevertheless, the engine was introduced in 2005 and was deemed the high-performance version of the HEMI until the 6.2L Hellcat was introduced.

The engine features a cast iron block with aluminum heads. The compression ratio of this engine depends on the application. For the HEMI SRT, the compression is rated at 10.9:1. while for the RAM trucks, it is rated at 10.0:1.

This original 6.4L engine was rated at 525 horsepower and 510 lb-ft of torque. But the newer versions that followed were detuned to 485 hp and 475 lb-ft of torque. And some export models like the ones found in the Chrysler 300 SRT are detuned even more and are rated at 370hp and 470lb-ft of torque.

The ones that were found in the RAM trucks were detuned even more compared to the regular engines. So, a 6.4L HEMI in the 2500 truck is producing 410 hp and 429lb-ft of torque.

6.4 HEMI Applications

The following models are the applications where you can find this engine:

  • Chrysler 300 SRT
  • Jeep Grand Wagoneer
  • Jeep Grand Cherokee SRT
  • Jeep Wrangler Unlimited Rubicon 392
  • Dodge Charger SRT 392
  • Dodge Challenger SRT 392
  • Dodge Durango SRT
  • RAM 2500, 3500, 4500, 5500

Chrysler 6.4 HEMI Problems

Now that we covered the applications of this engine, let’s move on and learn more about the common problems that this engine has.

  • Not Able To Tune
  • HEMI Tick
  • MDS Problems
  • Wrist Pin Failure

We briefly discussed the common problems with this engine and noted only a few of them. This already tells you that this engine is really reliable. But there are still some problems and in the following chapters, we are going to further elaborate on them in-depth.

Not Able To Tune

The first 6.4 HEMI problem that we are going to cover is connected to tuning. These engines do not like to be tuned. So, if you are planning to install an aftermarket camshaft and aftermarket supercharger, you might be risking totaling your engine.

The stock internals are simply not able to handle more power than normal. This is why through the years we have experienced detuning of the engine’s performance.

If when first released in 2005, this engine produced 525hp, now in trucks it only makes 410hp. All this reduction in power was in order for Chrysler to make the engine more reliable for heavy-duty use.

So, if you want to plan to create a lot of power with this engine, you are out of luck. You need to upgrade the internals if you want to squeeze more performance out of it, and even then the engine still might be unreliable and fail. So, be really wary of this issue if you are into tuning a 6.4L HEMI engine.


The second problem on our list of Chrysler 6.4 HEMI problems is the notorious HEMI tick. This ticking sound appears in all gen-three HEMI engines, especially in the 5.7L and 6.4L since these engines are pushed to great lengths in terms of mileage.

The engine will start to develop this ticking sound and there are a lot of conspiracies about why this is happening. Some people will say that you are using the wrong oil, and some will say that this is caused by worn-out lifters. There is no clear conclusion of why this problem appears.

But fortunately, it can’t total your engine. The only downside is that it is very annoying to deal with on a day-to-day basis.

So, you will have to experiment, either try different oil viscosity or replace the lifters and even the camshaft if these components are too worn out and cause this ticking sound to develop. It might be expensive but will probably sort out this problem permanently.

MDS Problems

Another very common Chrysler 6.4 HEMI problem with this engine is the MDS solenoid failure. So, what is MDS in the first place?

MDS stands for Multi-Displacement System. This system simply shuts off four cylinders and your engine technically turns into a V4.

This happens when the engine is not overloaded and the car can run with four fewer cylinders. By doing so, the car saves up to 20% fuel compared to the case when all cylinders are working.

What happens, in reality, is that all pistons are moving but in the ones that are turned off, there is no combustion, the spark does not ignite and there is no fuel.

This causes some problems because the engine is half warm and half cooled. And there can be issues. So, people often delete this system.

Also, another problem that people reported was connected with the solenoids that run this system. They can also fail and cause problems with the check engine light and also can worsen the engine performance. Now let’s move on to the next Chrysler 6.4 HEMI engine problems.

Wrist Pin Failure

And the last in our list of Chrysler 6.4 HEMI problems is a very serious issue. Namely, in some of the 2014 RAM models with this 6.4 engine, there were wrist pin failures reported. So, what is a wrist pin?

A wrist pin is a small pin that holds the piston connected to the rod. This component can fail and cause a piston slap or resemble a knocking noise. This sound appears overnight when the engine was left to cool off. And once you start the engine, the knocking sound will appear and will last for about 30 minutes until the engine warms up.

The models affected were the RAM 2500, 3500, 4500, and 5500. The engine codes affected are DJ, D2, DD, and DP.

Luckily, Chrysler is aware of this problem and they created a service bulletin on how this issue should be tackled. So, if you have one of these engines, you should take your truck to the RAM dealership and let them handle the problem. In most cases, the engine will have to be replaced.

6.4 HEMI Reliability

The 6.4L HEMI V8 has solid reliability besides the Chrysler 6.4 HEMI problems that we listed. This engine is pretty much a workhorse that is running on most RAM trucks nowadays.

There are no major issues with it, except for 2014 and the problem with the wrist pin that we noted in the previous chapter.

So, we would recommend that you try to avoid the 2014 model year trucks if you want to get a used truck. Besides that, this engine is pretty much bulletproof.

Another thing to add is to avoid tuning the engine while on stock internals. Make sure that you upgrade everything before you try to squeeze more power from it.


In this article, we have covered quite a bit when it comes to the Chrysler 6.4L engine. First, we covered the basic specs of this engine and the different power numbers it creates.

Then, we covered the common Chrysler 6.4 HEMI engine problems and learned more about what these issues are and how they are represented. Lastly, we discussed the overall reliability of this engine and whether or not it is a good option for you.


How Much HP Is A 6.4 HEMI?

The horsepower numbers of this engine really depend on the application. The most powerful version produces 525 hp, while the least powerful version of this engine produces only 410 hp. Usually, the truck models are the de-tuned versions of this engine.

What Kind Of Fuel Mileage Does A 6.4 HEMI Get?

The fuel mileage of this engine is rather poor compared to smaller displacement engines. In the RAM 2500, this engine gets 12 mpg in the city, 18 mpg on the highway, and 16 mpg combined. Even though, this is far-fetched. The real-world numbers average 15 mpg.

How Many Miles Does It Take To Break In A 6.4 HEMI

A break in time for any car engine is usually about 1,000 miles. For more specific information about this engine, you should consult the owner’s manual since in some engines these numbers can be lower.

What Are The Common 6.4 HEMI Problems?

Common problems with the 6.4 engine include lifter tick, MDS solenoid failure, and wrist pin failure on 2014 engines. You should be wary, especially with the wrist pin problem that often requires a complete engine replacement to get it sorted out.

Is The 6.4 HEMI Reliable?

Yes, this engine is fairly reliable. It should last for 250,000+ miles with no major issues. The only thing that breaks the reliability of this engine is the tuning, these engines are not tune-friendly on stock parts. They cannot handle the power. Upgrading the internals before you add a supercharger is a must.