6.4 HEMI Engine Review (Problems, Towing, MPG, Max Miles)

An engine is the core of a vehicle. It is the system that creates the power to move cars. And, among many machines you can find on vehicles today, maybe, 6.4 HEMI V8 Engine is one of the most popular engines. It uses a unique hemispherical combustion chamber design. This design allows it to increase the displacement as well as VCT.

Are you interested in getting one for your truck? Before you go to the workshop and get this engine, let’s find more about it. So, here is our 6.4 HEMI Engine Review for you.

Specifications – What is the 6.4 HEMI Engine?

First of all, let’s take a look at what this engine can do. This engine was released in several series. Each of them has a different capacity, which you can see from its name.

As for the 6.4 (liter) HEMI engine, it produces two different outputs. For the truck and pickup 6.4 HEMI engine, it can reach 410 horsepower. However, the standard cars that use this engine only produce 370 horsepower at peak performance.

6.4 HEMI Engine Review

The car or truck manufacturer combines a 6.4 HEMI engine with the three transmissions. They are the 66RFE six-speed automatic transmission or the G56 six speeds manual.

Some of the models also use the Aisin six-speed automatic transmissions. All of these are necessary to produce the best performance from this engine.

As we mentioned earlier, this engine uses hemispherical combustion chambers. Other than increased displacement and VCT, this design also affects the engine’s breathing. It increases the effectiveness of the intake and exhaust strokes process. Thanks to this design, the combustion efficiency increases multiple folds. Even more, this design also lowers the emission level.

This engine also uses one of the best materials to build exhaust gaskets. The maker uses a stainless steel material. Moreover, it’s not only an ordinary type of stainless steel. It is the same material you can find on the aircraft. Furthermore, this engine also has many cooling features.

You can find it on the pistons part and the standard oil cooler for better fluid dynamics. And, to increase its effectiveness, the advanced computational system controls fluid movement.

As you can see from our explanation above, the 6.4 HEMI engine is one of the best engines you can find on today’s vehicle. It doesn’t only produce top-quality performance and output. But, it is also very efficient compared to other engines.

Compatible Models

  •  2015-2018 Dodge Charger
  •  2015-2018 Dodge Challenger SRT 392 (R/T)
  •  2011-2014 Dodge Challenger SRT 8
  •  2014-Present Dodge Ram 2500 Pickup
  •  2015, 2017-Present Dodge Challenger SRT
  • 2016-2017 Ram 2500
  •  2016-2017 Ram 3500
  • Dodge Durango SRT8/SRT
  • Jeep Grand Cherokee SRT8
  • Chrysler 300 SRT8
  • 2018-Present Dodge Ram 3500 Pickup

Common RAM 6.4 Hemi Issues

It looks like a perfect engine for your vehicle. We also admit it as one of the most efficient engines ever created. However, we also found some of the problems that could have happened with this engine or the car that uses it.

  • Performance Decrease When Towing Heavy Load

This engine has a system that protects it from over-revving when you use it for towing. 6.4 HEMI engine activates this feature when you haul a heavy load. It will limit the output, so you can only run your truck at 35mph.

This feature looks great and helpful. However, thanks to this feature being activated mainly at the wrong place affect the engine performance. For that reason, it can’t produce the output that we want. This low performance also increases gas usage. It also affects the actual fuel economy of this engine.

  • Transmission Failure

This issue doesn’t happen a lot. However, when you experience this problem, get ready to have one of the worst days with your truck or car. It happens when you can’t change or use the gear that you want. In the worst case, your engine can’t even keep the gear in one level.

When the 6.4L Hemi transmission fails, the driver will hear a Clunking sound, sometimes Missing gears, and rough shifts.

Mostly, this problem happens because of the leak on transmission fluid. Moreover, you also hear a noise come out from the engine. Bring your car or other vehicles to the workshop to get the repair you need if you see that happen.

  • Problem with Engine’s Electrical System

An electrical problem also is one of many problems that could happen on your 6.4 HEMI engine. When it happens, your electrical system is just stopping working. It means you can’t use all kinds of features that your car has, such as a camera, radio, entertainment system, and others. However, the worst problem you can get from this issue is the effect on the speed control system. When it happens, your car performance drops, and the risk of an accident increases.

How Many Miles Will A 6.4 Hemi Last (Life Expectancy)

As you can see, the 6.4 HEMI engine is not perfect. Many issues could occur during the usage. Therefore, many people have this question about when they will get this engine for their vehicle. How long can this engine be used? We are talking about the engine lifespan here.

As we all know, the average lifespan of a vehicle engine is around 8 years. If we convert it into mileage, that would be about 150,000 miles of usage. So, if your car has been running that long or far, you might need to consider doing a major repair or even changing the engine or car with the new one.

How about a 6.4 HEMI engine? How long can it survive? This engine is one of the durable and robust engines you can find on the vehicle. The cool MDS (Multi-Displacement System) allows it to perform much better than many other engines. Moreover, this system also improves its fuel economy. Of course, if the towing problem above occurs, the good fuel economy will disappear.

However, the design allows it to run for around 300,000 miles. That is twice the average mileage of a standard car engine. In this case, this engine is the best. Therefore, people love its longevity because it can save a lot of money for maintenance and replacement. Moreover, its performance is also suitable for many kinds of purposes.

Is The 6.4 Hemi Good For Towing?

Even though we said that this engine could do many things, people still doubt its towing capacity. We also mentioned that some issues could occur when you use this engine for towing a heavy load. That makes us wonder. Is the 6.4 HEMI engine good for towing?

We determine the towing capacity of an engine by using the combination of engine horsepower, torque, and the towing feature of that vehicle. In simpler terms, an engine with high horsepower and torque has a higher towing capacity.

So, let’s take a look at the 6.4 HEMI engine horsepower and torque. This engine has maximum 410 horsepower output with 429 lb-ft @ 4,000 rpm of torque. According to an official source, this engine has a maximum towing capacity of 16,320 lbs and a payload of 4,050 lbs.

Compared to its rival, the 6.7L Cummins engine, the 6.4 HEMI engine’s towing capacity is lower. The Cummins engine produces 19,780 lbs of towing capacity. It means that the engine can two better than HEMI. However, we also need to see it from another perspective. HEMI uses gas fuel, while Cummins is a turbo diesel engine.

We all know that the diesel engine always has a bigger towing capacity than the gas engine. But, if you look at the slight difference in the two engines’ towing capacity, we can say HEMI is doing a pretty good job there. Even though it uses gas fuel, it can provide high towing capacity, close to the diesel engine.

Moreover, it also has a big payload. We can say that this engine is suitable for your towing purpose. Just make sure that you give it regular and proper treatment, so the issue won’t occur when you use it.

Does 6.4 Hemi Need Premium Gas?

Knowing that the 6.4 HEMI engine uses gas fuel, you might have an idea to give it the best gas fuel, a premium gas with high octane rating. Is it necessary? First of all, you must understand how those octane ratings affect your car engine performance.

The rating shows you the limit on how the fuel can withstand the pressure during the ignition process. When you start the engine, it will compress the fuel. After that, the compressed fuel will be ignited by spark plugs to start the chain reaction to produce the energy. This process has very high pressure, which can affect the engine part itself.

So, what is the recommended fuel for a ram 6.4L HEMI? According to RAM, the 6.4 HEMI engine is compatible with gas fuel with an 89 octane rating. You also can use a lower rating, such as 87. The engine can work well with that. However, it would help if you didn’t use a higher than 89, as it can damage the engine.

Conclusion – Is the 6.4 Hemi a good engine?

By looking at the 6.4 HEMI engine feature and performance that we explained above, we can only come to one conclusion. This engine is one of the best engines you can have for your vehicle. It has a long lifespan with high durability. Its performance and towing capacity are also satisfying. So, you don’t need to hesitate to get this one in your car.

Production years2011-present
Cylinder block materialCast iron
Cylinder head materialAluminum
Fuel typeGasoline
Fuel systemSequential multi-port injection
Number of cylinders8
Valves per cylinder2
Valvetrain layoutOHV
Bore, mm103.9 mm (4.09 in)
Stroke, mm94.6 mm (3.72 in)
Displacement, cc6,407 cc (392 cu in)
Type of internal combustion engineFour-stroke, naturally aspirated
Compression Ratio10.9:1 – 6.4L Hemi SRT;
10.0:1 – 6.4L Hemi Ram trucks
Power, hp366-485 hp (273-362 kW)/4,600-6,000
Torque, lb/ft429-475 ft-lb (582-644 Nm)/4,000-4,800
Engine weight500 lbs (227 kg) – dry weight
Firing order1-8-4-3-6-5-7-2
Engine oil weightSAE 0W-40
Engine oil capacity, liter6.7 l (7.0 qt) with oil filter
Oil change interval, mile6,000 (10,000 km)/6 months
6.4 Hemi Specification Table

6.4 HEMI Engine Review (Problems, Towing, MPG, Max Miles) Pictures

6.4L HEMI ENGINE REVIEW6.4 HEMI V8 Engine6.4 HEMI Engine Review