4 Common Ram 6.4 Hemi Problems & How to Fix Them

Only a few engines are as reliable as the RAM 6.4 HEMI. The high power and torque offered are undeniably among the most satisfying, though that may come with an unexpected price we don’t foresee.

What is that price? Well, there are a few common RAM 6.4 HEMI problems that could undermine the engine’s performance if car owners don’t pay enough attention to the signs.

Luckily, many symptoms will you know something is wrong with the engine. If you know them beforehand, you’ll be in a better position to react quickly and prevent them from even happening in the first place.

Before getting into that, let’s talk about what the HEMI 6.4 offers and why it’s the go-to engine for many drivers out there.


What is 6.4 HEMI?

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First included in the RAM 2500/3500 models back in 2014, the 6.4L HEMI V-8 engine came as a surprise due to its capacity to deliver more power than the 5.7L Hemi V-8.

And it was mainly because of the 6.4L’s astonishing peak rate of 410 HP when compared to 395 HP from the 5.7L

Among other reasons, the high power of the 6.4L Hemi had a lot to do with the lower governed engine speed.

Though it depends on the vehicle model and configuration, the engine can receive support from three transmission systems: 66RFE six-speed automatic, G56 six-speed manual, and the Aisin six-speed automatic.

For an improved and efficient performance, the engine features MDS, which stands for Multi-Displacement System.

It’s simple yet effective, as it turns off the fuel in the cylinders when the power is no longer needed. Despite running on 87 octane gasoline, the recommended fuel is 89 octane gas.

Now that we have a broader concept of what the 6.4L Hemi is let’s talk a bit more about the main features the engine has to offer.

Features of 6.4 HEMI Engine

Highly regarded as an efficient and reliable engine, the 6.4 HEMI has plenty of similarities with its predecessors while including new features that make it unique. Here are some of these features:

#Two Spark Plugs Per Cylinder

The engine has a total of 16 spark plugs, which would be two per each cylinder. These accessories allow the 6.4L HEMI to have improved combustion for more efficiency in performance and fuel economy. Plus, the plugs lead to reduced emissions.

#Oil-to-Water Oil Cooler

Another convenient feature found in the engine is the oil-to-water oil cooler, which provides additional cooling under harsh conditions.

Not only does this process make the engine safer, but it also prolongs its lifespan to continue working well for many years to come.

#Efficient Combustion Heat Removal

By featuring a highly efficient system, the engine guarantees no issues will get in the way, including combustion heat.

The 6.4 Hemi has piston cooling jets that effectively spray oil on the pistons’ bottom, efficiently removing combustion heat for better performance.

#An Effective Build

Much of an engine’s success depends on having high-quality parts. In this case, the aluminum cylinder heads offer an incredible combination with the hemispherical combustion chamber, thus delivering an efficient performance at all times.

#Fuel Flexibility

As mentioned before, the engine is capable of running using different fuel types.

Though the recommended option would be to use 89 octane gasoline, this equipment is more than capable of doing fine while using 87 octane gasoline for its operations.

#Familiar Architecture

If you’ve experienced handling the 5.7L Hemi V-8, you’ll find that the architecture of the 6.4 Hemi is similar to it. However, some differences are noticeable, such as the bore diameter and stroke length.

The 4 Common Ram 6.4 Hemi Problems

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Despite being a robust, reliable, and efficient engine, the 6.4 Hemi has some common issues that car owners may eventually face. Want to know what those problems are? Check them out below:

01. Transmission Failure

While it isn’t a regular issue, one of the most common problems reported in the 6.4 HEMI engine is transmission failure. These issues can be the result of many things but knowing how to run diagnostics is essential to get the problem solved.

But how do you know if the engine has transmission failure? Here’s a list of symptoms that may indicate the engine has this problem.

  • Transmission is unable to engage or stay in gear.
  • Delayed shifts or gears are missing.
  • High revving or slipping transmission.
  • The engine’s transmission fluid leaks.
  • Constant, noticeable burning smell.
  • Noises, such as buzzing or humming.
  • The car doesn’t have power.
  • Active Check Engine Light.

If you notice any of those issues, then that’s a clear indication that there’s transmission failure.

02. Power Control Failure

Considering the vehicle’s engine control unit can be complex, it’s often difficult to figure out when it fails.

However, multiple signs should warn you the engine may be having these issues, which is why being fully aware of every minor change in performance is necessary.

  • Intermittent Cylinder Malfunctions.
  • Turned on Check Engine Light.
  • The vehicle fails to start.

These are only a few of the most noticeable symptoms of a power control module failure. Keep in mind that these issues may be intermittent, meaning that you could experience them sporadically.

03. Electrical Issues

Another common problem directly affects the vehicle’s overall performance, as it can interfere with the electricity that controls radio, cameras, and other features inside the car.

Sometimes, these just stop working, which is both disappointing and frustrating.

If the situation gets worst, this problem can end up impacting the speed control systems. After running diagnostics, it’s clear that these issues are often the result of a vehicle’s electrical system failure.

04. Ticking Problems

If you’ve been experiencing a ticking sound recently, you should know that you’re not alone.

It’s a common problem not only for this engine but for the previous HEMI engines as well. Undoubtedly, the ‘HEMI tick’ remains one of the major 6.4 HEMI cam and lifter problems even to this day.

The possible reasons for this issue are many. For example, wrongly-sized valve stems could lead to valve chatters, which is the ticking sound we often hear.

Alternatively, this issue could be the result of stuck lifters that grind against the camshaft.

Other features to consider would be the lifters, the fuel quality, and the injectors that may not be working correctly.

Possible Solutions of Problems with 6.4 HEMI Engine

It may sound cliché, but the amount of problems you can avoid by adequately maintaining the engine is astonishing.

While these possible solutions may not end up solving all of the RAM 6.4 HEMI problems, they may still prevent a lot more issues that you’d have to face inevitably.

Here’s what you must do to solve the problems mentioned above and prevent any more incidents in the future.

01. For Transmission Failure

As we learned earlier, a vehicle that refuses to go into gear may be having transmission failure.

Often caused by low transmission fluid or leaks, the solution to this issue is finding the dipstick, removing it, wipe it clean, put it back in its place, and get it out again.

Then, look out for the fluid’s level, smell, and color — If there’s little fluid, try adding more liquid. In case you notice a burnt smell or dark brown color, it’d be a good idea to contact a transmission specialist.

02. For Ticking Problems

A practical solution to eliminate the ticking problem would be to carry out routine maintenance checks on the vehicle’s engine.

A thorough inspection will let us know if there’s any malfunction that could be causing this issue, and we’d be in a better position to think of solutions.

Additionally, you want to inspect the engine oil levels regularly and use the recommended type of oil. In most cases, these sounds result from inadequate lubrication, which is an issue you can solve very quickly.

The Hemi tick is such a common issue that there are many potential solutions. Check out this video for more information on this matter.

03. For Other Common Problems

If you’ve been experiencing 6.4 Hemi camshaft problems, electrical issues, or power control failure, regular maintenance is the solution to those problems.

That’s not just staring at the engine waiting for something to happen, but rather regular replacement of individual parts that wear down after thousands of miles.

Since maintenance is a broad term that encapsulates many tasks, we will be giving you several tips to keep the engine up and running later on in the article.

Pros & Cons of 6.4L Hemi Engine

While it’s true that the 6.4 HEMI isn’t perfect, the truth is that it still outperforms most of the competition by a long mile. And, even if the engine has some issues like mentioned above, they’re not regular occurrences.

The point is, the advantages of this engine outshine its few flaws. To give you a better idea about what we mean, here’s a list of pros and cons that you can expect from this engine model.


  • Built around a cast-iron cylinder block with a 90-degree design for enhanced durability.
  • Efficiently removes combustion heat via the oil spray.
  • Provides more power and torque than its predecessor, the 5.7L model.
  • Suitable for operations like hauling or towing.
  • Updated version available for Ram 2500/3500 trucks, Ram 3500/4500/5500 cab chassis.
  • It features the Multi-Displacement System for more efficiency.
  • The engine runs on standard 87 octane gasoline, though the recommended fuel is 89 octane gas.
  • The aluminum cylinder heads are reliable and resistant.


  • Much like the previous engines from the brand, this one has a ticking sound

Maintenance Tips

If you want to avoid any engine problems — common or uncommon — proper and regular maintenance is necessary.

Not sure what to do to keep your 6.4 HEMI in good shape? Don’t worry! Here’s a list of maintenance tips to help you with that.

Engine Oil Change

Changing the engine oil and the filter is a maintenance task that shouldn’t escape your schedule. Though it depends on several factors, every 4,000 to 6,000 miles would be the perfect moment to do it.

Tire Rotation

Usually, you’d want to rotate tires following the oil change. Poor alignment or unbalanced tires can lead to uneven wear, which is not what we want.

Front End Alignment

Proper alignment allows the tires to make contact with the roads at the right angle, which leads to a better experience on the road. Ideally, doing this alignment is necessary at least once a year.

New Engine Air Filter

Replacing the air filter every 15,000 miles allows the engine to receive clean air essential for the combustion process.

Adjusting Parking Brake. The parking brake keeps the car from rolling to avoid accidents. Adjusting the brake is necessary every 30,000 miles.

Spark Plugs

If you want no problems with 6.4 HEMI engines, replacing the spark plugs every 100,000 miles is necessary. Changing the plugs guarantees high efficiency and reliable performance from the engine.

Coolant Service

Required every ten years or every 150,000 miles, coolant service is necessary to keep the engine running in extreme temperatures.

Automatic Transmission Service

Transmission flushing is crucial every 60,000 miles, as it’ll save you a lot of trouble you’d have to face if you don’t do this maintenance task.

PCV Valve

Keeping the PCV system in good condition every 100,00 miles is also an essential maintenance task. This system eliminates dangerous oil vapors from the engine while also avoiding those vapors from releasing into the atmosphere.

Serpentine Belt

This simple piece of equipment keeps the engine from losing power steering, A/C malfunctions, and 6.4 HEMI thermostat problems, to name a few. To avoid that, consider changing the serpentine belt every 100,000 miles.


While RAM 6.4 HEMI problems are almost inevitable, knowing the most common issues and their possible solutions beforehand will help you tackle any situation. If it gets out of hand, you can head to a specialist to get suggestions on what to do.

Nonetheless, if you follow our maintenance recommendations thoroughly, you may not even get to witness these problems in the first place.