6.4 HEMI Engine Problems
The Chrysler 6.4 Hemi debuted in 2005 with 525 horsepower and 510 torque. This variant is the crate engine under the name 392 HEMI. It wasn’t until 2011 that Chrysler actually began selling cars with the 6.4L V8 Hemi engine. Power output for factory cars comes in a bit lower than the crate engines. However, it remains a powerful performance engine. The 6.4L Hemi is also a pretty strong, reliable engine. Though, no engine is flawless and there aren’t any exceptions here. In this guide, we’ll discuss a few of the common 6.4 Hemi engine problems along with overall thoughts on reliability.
*We may refer to the 6.4 HEMI as the 6.4L HEMI, 392 Apache, 392 HEMI, FCA 6.4 HEMI, Dodge, Jeep, Chrysler, or Ram 6.4 HEMI. It’s all in reference to the same engine.
392 HEMI Background Info
A few common names for the 6.4 HEMI include 392 HEMI and 392 Apache. The 392 represents the engine size in cubic-inches while Apache is the codename for the 6.4L Hemi engine. One important note – the 392 HEMI crate engine shares few parts with the actual 6.4 Hemi available in factory cars. It’s a little odd since they both share the same names and displacement. However, the crate engine is a bit stronger and more performance oriented.
That’s not to say the factory 6.4 is any slouch, though. In 2011, SRT8 models first receive the 6.4L HEMI with 470 horsepower and 470 torque. In 2015, output was increased to 485 horsepower and 475 torque. Ram 2500 and 3500 models receive a lower output variant of the engine. This was due to a need for better fuel economy and a better powerband for towing.
What Cars Use the 6.4L HEMI?
The 392 HEMI is in the following vehicles from Dodge, Jeep, Chrysler and Ram:
- 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 like the Ram 2500 and 3500 have multiple engine options. However, the 6.4 HEMI V8 remains an option for all of the above vehicles. Again, Ram trucks receive a slightly lower output variant that’s better suited to efficiency and towing.
Some of the issues we discuss in this post may affect certain vehicles more than others. A lot likely comes down to the specific use of each Dodge, Jeep, Chrysler, or Ram using the 6.4L HEMI.
4 Most Common 6.4 HEMI Problems
A few of the most common problems on the Chrysler, Dodge, and Ram 392 Apache engine include:
- Multi Displacement System (MDS)
- Engine Tick
- Transmission Failure
We’ll circle back to this point towards the end of the post, but we want to clarify this now. The 392 HEMI is a reliable engine. We’re classifying the problems as a few of the most common. That’s not to say any of these problems affect a large percent of 6.4 HEMI engines. Also, other failures can and do happen from time to time so this is by no means an exhaustive list.
That said, let’s dive in and discuss each of the above problems one by one. At the end of the post we’ll bring things full circle and wrap it up with some thoughts on Chrysler 6.4L reliability.
1) 392 HEMI Multi-Displacement System Faults
Multi-displacement system (MDS) is a promising technology. While cruising the 6.4 HEMI is able to shut down 4 of the 8 cylinders. It’s a great way to use a larger engine to pump out more power while remaining efficient during lower power situations. However, it’s still relatively new technology. The main issue with the 392 HEMI MDS seems to be solenoid failures. Some also claim the 6.4 V8 MDS can feel a little clunky at times. Fortunately, the system can be manually shut off so all 8 cylinders are always firing.
There are a few long-term concerns about multi-displacement systems in general. For one, the 392 Apache MDS always shuts down the same 4 cylinders. Why could this be an issue? Well, there’s a lot of heat generated by the combustion process. Some of that heat is good. If the 6.4 HEMI shuts down 4 cylinders for an extended period those cylinders could run cooler. All reciprocating parts are still moving when the cylinders shut down. Allowing them to run cooler may cause longer-term issues with poor lubrication.
There’s some more that goes into that, but we’ll avoid writing hundreds more words and getting too technical. Point is – MDS is promising technology, but has a few small kinks like solenoid failures. It’s also too new to say how the 6.4 HEMI MDS may impact reliability and engine longevity.
6.4L HEMI MDS Issues Are Speculation
The MDS solenoid failures can and do occur on the 392 HEMI engine. However, long-term effects of multi-displacement systems are still speculation. Shutting down the same 4 cylinders for an extended period can have a negative impact. Spark plugs may foul quickly when they run too cold and are suddenly called back to use. Oiling is a potential concern on colder cylinders. Cylinders on the 6.4 HEMI may wear down unevenly over time. The list goes on and on. It’s purely speculation, but there are basic engineering concepts that suggest MDS could have negative impacts on longevity.
2) 6.4 HEMI Engine Tick Problems
Engine ticking on the 392 HEMI may tie into a few of the other common problems in this article. Specifically, the above MDS discussion. Ticking on the FCA 6.4 HEMI engine is an interesting issue. There are some claims that state the ticking is normal and will not affect longevity, reliability, or performance. However, some engine ticks have also led to complete engine replacement of the 6.4L HEMI. A few common causes of 6.4 HEMI engine tick include:
- Faulty lifters
- Seized lifter rollers
A few other minor things may lead to ticking on the Dodge 392 HEMI V8. However, our primary focus is on the above two bullets. This is also a common issue on the 5.7 HEMI. Lifter or lifter roller problems may be partially attributed to the multi-displacement system. It may not be the only cause, but it does make some sense. Lifter problems on the 6.4 HEMI likely boil down to poor oil flow over the lifter rollers which causes them to seize. Once this occurs, the lifter contacts the cam lobes and produces an audible engine ticking noise.
Of course, metal on metal contact also results in shavings of metal entering the engine oil. Usually the oil filter will catch most of this metal if the 392 HEMI lifter problems are caught quickly. If left too long it’s possible for further engine damage to occur.
392 HEMI Lifter Roller Symptoms
Look for the following symptoms that may indicate a fault with the 6.4 HEMI lifter rollers:
- Check engine light
Problems with the 6.4 HEMI lifters can be tough to diagnose. It’s often simply the ticking sound without any other symptoms. This makes it especially challenging since others seem to notice 392 Apache ticking without any actual problems. In some cases, you may notice misfires or receive a check engine light – usually as the problem becomes severe.
The unlucky few who run into lifter roller failures typically notice issues around 80,000 to 120,000 miles. The below video is mostly in reference to the 5.7 HEMI, but it’s a good resource for more information on FCA 6.4 ticking and lifter rollers.
HEMI 6.4L Lifter Roller Replacement
If caught quickly it’s unlikely additional engine damage will occur. However, at the least the engine will need to be opened up to replace the camshaft. Parts and labor on 6.4 HEMI cam replacement can quickly add up to $2,000+. Tack on some extra in the case metal shavings take out other parts like the oil pump. It’s possible for parts and labor to exceed the cost of a new remanufactured engine. As such, some replace the entire 392 HEMI engine.
3) FCA 392 HEMI Transmission Failures
We’ll speed things up a bit moving through transmission and misfire problems on the 6.4 HEMI. Some of the 392 HEMI engines are mated to different transmissions. This of course depends on whether you’re talking about Dodge Charger’s or Ram 3500’s, for example. Problems appear to mostly occur on Ram 2500 or Ram 3500 trucks. It also may not be fair to consider these transmission failures among the most common issues.
It’s reasonable to assume many Ram 2500 and 3500 trucks are subjected to tough conditions towing heavy loads. This can put a lot of stress on a transmission and lead to premature wear and failure. Nonetheless, transmission problems can and do occur on Dodge, Chrysler, and Jeep models from time to time.
Again, it’s a very small percentage of failures. It is, however, worth the mention since it can be a costly issue.
6.4L HEMI Transmission Failure Symptoms
A few symptoms of transmission failure on the 392 HEMI include:
- Clunking sounds
- Missing gears
- Rough shifts
There are a few other possible symptoms, too. However, the transmission slipping, clunking, missing gears, or shifting too rough may indicate potential problems. Depending on the extent of the issues, you may need a new transmission for the FCA 6.4L Hemi V8.
392 HEMI Transmission Replacement
A transmission rebuild may be possible or a new trans may be needed. Either way, replacing the 6.4 transmission can add up to thousands of dollars. It’s not a problem we would put too much concern into. Transmission failures only affect a very small percent of vehicles.
4) 6.4 HEMI Engine Misfire Problems
Misfires can potentially be due to lifter roller or MDS solenoid issues. It’s also not totally fair to consider 392 HEMI misfires to be an actual problem. Misfires are often due to normal wear and tear items like spark plugs and ignition coils. That or misfires are simply a symptom of another underlying problem. Anyways, we’re really focusing on spark plugs here.
6.4 HEMI engines use 16 spark plugs. Yes, that’s correct – the 392 HEMI uses 2 spark plugs per cylinder. Then there are the standard 8 ignition coils. It’s a lot of ignition parts that may cause engine misfires. Spark plugs are wear and tear parts that usually require replacement every 60,000 to 80,000 miles. Ignition coils typically last about twice as long.
Premature failures aren’t too common on the 6.4 HEMI. However, it can happen especially with 16 spark plugs. Nonetheless, these are usually basic maintenance items. Don’t overlook spark plugs and ignition coils.
392 HEMI Misfire Symptoms
Symptoms of misfires on the Dodge, Ram, Chrysler, Jeep 6.4 HEMI include:
- Fault codes
- Rough idle
- Poor performance
A misfire will likely trigger a fault code. You might also notice the 392 HEMI is stuttering, idling rough, or down on power. Most won’t notice the power loss since the engine will still be functioning properly on the other 7 cylinders.
6.4 HEMI Plugs & Coil Replacement
Again, spark plugs are normal wear and tear parts on the 392 HEMI. Replacement is normal every 60,000 to 80,000 miles. Those who push their 6.4 HEMI’s hard may require earlier repairs. A set of 16 spark plugs come in around $100-150. It’s also a pretty simple DIY that most can knock out easily in the driveway. Ignition coils are a bit pricier, but typically last about 2x as long as the 6.4 spark plugs.
Chrysler, Dodge, Jeep, Ram 6.4 HEMI Reliability
How reliable is the 392 HEMI? Overall, the FCA 6.4 HEMI is a solid, reliable engine. It’s certainly not the most reliable engine in the world, but it’s also far ahead of the worst. We’ll give the 392 HEMI above average remarks for reliability. It’s powered many flagship Dodge, Jeep, Chrysler, and Ram vehicles for nearly a decade. The 392 Apache HEMI engine is a fun, powerful workhorse that’s withstood the test of time. While a few of the common problems discussed can be pretty costly they affect a pretty small number of engines.
That said, a lot of 6.4 HEMI reliability and longevity comes down to maintenance. It’s one of the things we can control. Ensure you’re using quality oils and changing it on time. If and when problems do pop up then repair them as soon as possible. With proper maintenance, chances are most 392 HEMI engines will hold up well beyond 200,000 miles.
6.4 HEMI Common Problems Summary
The 6.4 HEMI first began its life as a crate engine under the name 392 HEMI. In 2011, FCA began using the 392 Apache in production models beginning with the Dodge Challenger SRT8. Since then the engine found its way into many flagship performance models and trucks. It’s a stout engine that provides respectable performance and reliability. However, no engine is perfect.
A few of the most common problems on the 6.4 HEMI include MDS solenoids, lifter rollers, transmissions, and engine misfires. Some of the issues are potential effects of the 392 HEMI MDS system. That can, however, be manually disabled. While a few of the 392 HEMI problems can be expensive they only affect a pretty small number of engines.
All in all, the FCA 6.4 HEMI is a great engine. Maintain it well and fix issues in a timely manner when they do pop up. Otherwise, expect the 392 HEMI to last north of 200,000 miles in most cases.
What’s your experience with the 6.4 HEMI V8 engine? Are you considering one?
Drop a comment and let us know!