6.4 HEMI Engine Problems
The Chrysler 6.4 Hemi made its debut in 2005, producing 525 horsepower and 510 pound-feet of torque. This is the crate engine known as the 392 HEMI. Chrysler did not begin selling vehicles equipped with the 6.4L V8 Hemi engine until 2011.
Factory cars produce slightly less power than crate engines. Nonetheless, it is a potent performance engine. Additionally, the 6.4L Hemi is a fairly powerful and reliable engine. However, no engine is perfect, and this is no exception.
We’ll discuss a few of the most common 6.4 Hemi engine issues in this guide, as well as our overall thoughts on reliability.
*The 6.4 HEMI may also be referred to as the 6.4L HEMI, the 392 Apache, the 392 HEMI, the FCA 6.4 HEMI, the Dodge, Jeep, Chrysler, or Ram 6.4 HEMI. It’s all about the same engine.
392 HEMI Background Info
The 6.4 HEMI is also known as the 392 HEMI and 392 Apache. The 392 denotes the engine’s cubic-inch displacement, while Apache refers to the 6.4L Hemi engine’s codename. One critical note – the 392 HEMI crate engine shares very few components with the factory-installed 6.4 Hemi.
It’s a little strange because they both have the same names and are located in the same location. The crate engine, on the other hand, is slightly stronger and more performance-oriented.
That is not to say that the factory 6.4 is a slouch. SRT8 models received the 6.4L HEMI engine with 470 horsepower and 470 lb-ft of torque for the first time in 2011. In 2015, the engine was upgraded to 485 horsepower and 475 lb-ft of torque.
Ram 2500 and 3500 models are equipped with a lower-output engine. This was done to improve fuel economy and to provide a more powerful powerband for towing.
What Cars Use the 6.4L HEMI?
The 392 HEMI engine is found in the following Dodge, Jeep, Chrysler, and Ram vehicles:
- Dodge Charger SRT8, SRT 392, R/T Scat Pack
- Dodge Challenger SRT8, SRT 392, R/T Scat Pack
- Chrysler 300 SRT
- Jeep Grand Cherokee SRT
- Dodge Durango SRT
- Ram 2500
- Ram 3500
Certain models, such as the Ram 2500 and 3500, come with a variety of engine options. The 6.4-liter HEMI V8 engine, on the other hand, remains an option for all of the above vehicles. Once again, Ram trucks receive a slightly reduced output variant that is more suited to efficiency and towing.
Certain issues discussed in this post may have a greater impact on certain vehicles than others. Much will likely depend on the specific application of each Dodge, Jeep, Chrysler, or Ram equipped with the 6.4L HEMI engine.
4 Most Common 6.4 HEMI Problems
Several of the most frequently encountered issues with the Chrysler, Dodge, and Ram 392 Apache engine include the following:
- Multi Displacement System (MDS)
- Engine Tick
- Transmission Failure
We’ll return to this point near the end of the post, but we’d like to address it now. The 392 HEMI engine is a dependable performer. We’re categorizing the issues as a few of the most prevalent.
That is not to say that any of these issues affect a significant proportion of 6.4 HEMI engines. Additionally, additional failures can and do occur on occasion, so this is by no means an exhaustive list.
With that in mind, let us dive in and address each of the aforementioned issues one by one. At the conclusion of this post, we’ll bring things full circle and discuss the reliability of the Chrysler 6.4L engine.
1) 392 HEMI Multi-Displacement System Faults
MDS is a promising technology. The 6.4 HEMI is capable of shutting down four of the eight cylinders while cruising. It’s an excellent way to maximize the output of a larger engine while remaining efficient in low-power situations.
Nonetheless, it is a relatively new technology. The 392 HEMI MDS’s primary issue appears to be solenoid failures. Additionally, some claim that the 6.4 V8 MDS can feel clunky at times. Fortunately, the system can be turned off manually, ensuring that all eight cylinders always fire.
In general, there are a few long-term concerns with multi-displacement systems. For starters, the 392 Apache MDS consistently disables the same four cylinders. Why might this be a problem? To be sure, the combustion process generates a great deal of heat. Some of that heat is beneficial.
If the 6.4 HEMI engine is forced to shut down four cylinders for an extended period of time, those cylinders may run cooler. When the cylinders are turned off, all reciprocating parts continue to move. Allowing them to run cooler may result in longer-term lubrication issues.
There is more to that, but we will avoid writing hundreds of additional words and becoming too technical. The point is that MDS is a promising technology, but it does have a few minor flaws, such as solenoid failures. Additionally, it is too early to determine how the 6.4 HEMI MDS will affect reliability and engine longevity.
6.4L HEMI MDS Issues Are Speculation
MDS solenoid failures on the 392 HEMI engine are possible and do occur. However, the long-term effects of multiple displacement systems remain a matter of conjecture.
Disabling the same four cylinders for an extended period of time can have a detrimental effect. Spark plugs can quickly foul if they are run too cold and then called back into service. On colder cylinders, oiling may be a concern.
The 6.4 HEMI’s cylinders may wear unevenly over time. The list could go on indefinitely. While this is pure speculation, there are some fundamental engineering concepts that suggest MDS may have a detrimental effect on longevity.
2) 6.4 HEMI Engine Tick Problems
Engine ticking on the 392 HEMI may be related to a few of the other frequently encountered issues discussed in this article. More precisely, the preceding MDS discussion.
The FCA 6.4 HEMI engine ticking is an intriguing issue. Certain claims assert that ticking is normal and will have no effect on the device’s longevity, reliability, or performance.
However, certain engine ticks have necessitated the complete replacement of the 6.4L HEMI engine. Several common causes of 6.4 HEMI engine ticking include the following:
- Faulty lifters
- Seized lifter rollers
Several other minor factors may contribute to the Dodge 392 HEMI V8 ticking. Our primary focus, however, is on the preceding two bullets. This is also a frequent occurrence with the 5.7 HEMI. The multi-displacement system may be partially responsible for lifter or lifter roller problems.
While this is not the only explanation, it does make some sense. Lifter problems on the 6.4 HEMI are almost certainly due to insufficient oil flow over the lifter rollers, causing them to seize. When this occurs, the lifter makes contact with the cam lobes, resulting in an audible ticking noise from the engine.
Naturally, metal on metal contact results in metal shavings entering the engine oil. Typically, the oil filter will capture the majority of this metal if the 392 HEMI lifter issues are addressed promptly. If left unattended for an extended period of time, additional engine damage may occur.
392 HEMI Lifter Roller Symptoms
Examine the following symptoms to determine if there is a problem with the 6.4 HEMI lifter rollers:
- Check engine light
Diagnosing problems with the 6.4 HEMI lifters can be challenging. Often, it’s just the ticking sound with no other symptoms. This makes it all the more difficult, as others appear to notice 392 Apache ticking along without incident. You may notice misfires or a check engine light in some cases – usually when the problem becomes severe.
The unfortunate few who experience lifter roller failures typically do so between 80,000 and 120,000 miles. While the video below is primarily about the 5.7 HEMI, it is an excellent resource for additional information on FCA 6.4 ticking and lifter rollers.
HEMI 6.4L Lifter Roller Replacement
If caught quickly, additional engine damage is unlikely. However, the engine will have to be opened up in order to replace the camshaft. The cost of parts and labor for 6.4 HEMI cam replacement can easily exceed $2,000+. Add some extra metal shavings to the case and remove other components such as the oil pump. Parts and labor costs may exceed the cost of a new remanufactured engine. As such, some of them completely replace the 392 HEMI engine.
3) FCA 392 HEMI Transmission Failures
We’ll move quickly through transmission and misfire issues with the 6.4 HEMI. Certain HEMI engines are mated to a variety of transmissions. This, of course, is dependent on whether you’re discussing Dodge Chargers or Ram 3500s.
The majority of issues appear to occur on Ram 2500 or Ram 3500 trucks. Additionally, it may not be fair to classify these transmission failures as common.
It’s reasonable to assume that many Ram 2500 and 3500 trucks operate in difficult conditions while towing large loads. This places a great deal of strain on the transmission, resulting in premature wear and failure. Nonetheless, transmission problems do occur occasionally on Dodge, Chrysler, and Jeep models.
Again, this is a negligible proportion of failures. It is worth noting, however, because it can be a costly issue.
6.4L HEMI Transmission Failure Symptoms
The following are a few symptoms of transmission failure on the 392 HEMI:
- Clunking sounds
- Missing gears
- Rough shifts
Additionally, there are a few additional possible symptoms. However, slipping, clunking, missing gears, or excessively rough shifting may indicate potential problems. Depending on the severity of the issues, you may require a new FCA 6.4L Hemi V8 transmission.
392 HEMI Transmission Replacement
A rebuild of the transmission may be possible, or a new transmission may be required. In either case, the 6.4 transmission replacement can cost thousands of dollars. This is not a matter we would take too seriously. Transmission failures occur in a minuscule percentage of vehicles.
4) 6.4 HEMI Engine Misfire Problems
Misfires could be caused by a problem with the lifter roller or the MDS solenoid. Additionally, it is not entirely fair to consider 392 HEMI misfires to be an issue. Misfires are frequently the result of normal wear and tear on components such as spark plugs and ignition coils. That, or misfires are merely a symptom of a more fundamental issue. Anyway, we’re primarily concerned with spark plugs here.
Sixteen spark plugs are used in 6.4 HEMI engines. That is correct; the 392 HEMI engine utilizes two spark plugs per cylinder. After that, there are the eight standard ignition coils. There are numerous ignition components that can contribute to engine misfires.
Spark plugs are consumable components that should be replaced every 60,000 to 80,000 miles. Typically, ignition coils last approximately twice as long.
On the 6.4 HEMI, premature failures are uncommon. However, it is possible, particularly with 16 spark plugs. Nonetheless, these are typically low-cost preventative maintenance items. Spare no attention to spark plugs and ignition coils.
392 HEMI Misfire Symptoms
Symptoms of a misfire on a Dodge, Ram, Chrysler, or Jeep 6.4 HEMI engine include the following:
- Fault codes
- Rough idle
- Poor performance
A misfire will almost certainly result in the activation of a fault code. Additionally, you may notice the 392 HEMI stuttering, idling rough, or lacking power. Most drivers will not notice the power loss because the engine will continue to operate normally on the remaining seven cylinders.
6.4 HEMI Plugs & Coil Replacement
Again, spark plugs are a component that is subject to normal wear and tear on the 392 HEMI. Every 60,000 to 80,000 miles, the engine should be replaced. Those who abuse their 6.4 HEMI engines may require repairs sooner.
A set of sixteen spark plugs costs between $100 and $150. Additionally, it’s a fairly simple do-it-yourself project that the majority of homeowners can complete in their driveway. Ignition coils are slightly more expensive, but typically last approximately twice as long as 6.4 spark plugs.
Chrysler, Dodge, Jeep, Ram 6.4 HEMI Reliability
How trustworthy is the 392 HEMI? In general, the FCA 6.4 HEMI engine is a solid, dependable performer. While it is not the most reliable engine on the market, it is light years ahead of the worst. We’re going to give the 392 HEMI an above-average rating for dependability. For nearly a decade, it has powered numerous flagship Dodge, Jeep, Chrysler, and Ram vehicles.
The Apache 392 HEMI engine is a dependable, fun-to-drive workhorse that has stood the test of time. While several of the discussed issues can be quite costly, they affect a relatively small number of engines.
Having said that, a significant portion of 6.4 HEMI reliability and longevity is determined by maintenance. It is one of the things over which we have some control. Ascertain that you are using high-quality oils and replacing them on a regular basis.
If and when problems do occur, they should be addressed immediately. The chances are that the majority of 392 HEMI engines will last well beyond 200,000 miles with proper maintenance.
6.4 HEMI Common Problems Summary
The 6.4 HEMI engine originally debuted as the 392 HEMI crate engine. Beginning with the Dodge Challenger SRT8, FCA began using the 392 Apache in production models in 2011.
Since then, the engine has been incorporated into a plethora of high-performance cars and trucks. It’s a dependable engine with respectable performance and reliability. No engine, on the other hand, is faultless.
MDS solenoids, lifter rollers, transmissions, and engine misfires are just a few of the more common issues with the 6.4 HEMI. Several of the concerns concern the 392 HEMI MDS system’s potential effects. However, this can be turned off manually. While some of the 392 HEMI issues are costly, they affect a relatively small number of engines.
In sum, the FCA 6.4 HEMI engine is an excellent performer. Maintain it properly and promptly address issues that arise. Otherwise, the 392 HEMI should typically exceed 200,000 miles.
How is the 6.4 HEMI V8 engine performing for you? Consider purchasing one.
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