6 Best Spark Plugs for 4.0 Jeep [Reviews & Buying Guide]

Looking for the best spark plugs for 4.0 jeep? Getting all confused with various types of spark plugs? Then don’t get stressed about that, you will find all the necessary information here.

First, let’s find out why our vehicles need spark plugs! The main function of the spark plug is to provide electric energy to a combustion chamber to create a spark to ignite the concentrated air-fuel mixture.

Spark plugs have other usages too! They are used to monitor the ionization inside the cylinder. Sometimes they are also used in furnaces to ignite a combustible fuel-air mixture.

So, there are different spark plugs that are suitable for 4.0 jeep wrangler, but we are going to discuss the Six best spark plugs for 4.0 jeep.

Best Spark Plugs for 4.0 Jeep – Comparison Table

6 Best Spark Plugs for 4.0 Jeep Reviews

You have already a quick comparison of these 6 spark plugs. Now, let’s check out the plugs that are suitable for 4.0 Jeep with detailed features and specifications.

1. NGK V-Power Spark Plugs

For almost any automotive use, NGK V-Power spark plugs give a cost-effective performance. You can refer them as one of the best spark plugs for jeep 4.0 wrangler since they require lower voltage to ignite the mixture so that complete combustion can happen.

These Spark Plugs are efficient because they have a V-Cut in the center electrode that produces a sufficient spark to improve ignition.

Though it is very simple in design, you can surely rely on the NGK V-power spark plug for quality.

Features and Benefits

Reliable threads and metal plate

Cold-rolled threads help to avoid damage to the engine cylinder head and also trivalent metal plate offers anti-corrosion characteristics.

Solid copper core

Where other spark plugs have a copper-coated core, NGK V-power has a solid copper core, which offers better hear transfer and conductivity for higher fuel efficiency and reduced emission.

Excellent Performance

Built according to OEM specifications, they provide better performance than the conventional ones. Also, their insulator of alumina silicate ensures high heat transfer.

Pros

• Very easy to install
• Highly resilient for chemical and electrical wear.
• A unique rib design avoids spark flashover.
• Hundreds of models are available.

Cons

• Tends to become brittle over time.

2. Bosch Double Iridium OE Spark Plug

Bosch Double Iridium Spark Plugs are designed to provide high performance and a long lifespan. Their pin-to-pin program substantially decreases quenching.

Construction complies with OEM criteria ensuring maximum performance. You can install these spark plugs in advanced-engine European and Asian vehicles establishing themselves as they are also considered the best spark plugs for Jeep Cherokee as well as the best spark plugs for 2002 Jeep Grand Cherokee.

Features and Benefits

Longer Lifespan

Compared to regular copper plugs, the Bosch spark plugs have a firing pin made of double Iridium and ground electrodes graving which give 4 times longer operational life.

Greater Reliability

Its 360-degree consistent laser program keeps a secure bond of the metal pin; so that the central electrode doesn’t face any type of crack, thus provides better durability and higher heat transfer.

Superior Ignition

Firing pin made of 0.6-millimeter firing pin offers greater ignitability, helps in proper combustion, and ensures better performance; so you can enjoy a comfortable ride.

Pros

• Faster installation.
• Easy replacement.
• Seven years of satisfactory performance.
• Doesn’t require anti-seize to avoid corrosion.

Cons

• The gaps may not be correct.

3. Autolite XP985-4PK Iridium XP Spark Plug

Designed and built in the USA, Autolite Iridium XP spark plug has finewire design and platinum sidewire program which serves for better reliability and improved ignitability.

These 4.2 x 3.6 x 1.1 inches spark plugs are the best spark plugs for 4.0 jeep since they are suitable for heavy performance engines. You can always rely on them as they are cheap as well as long-lasting.

Features and Benefits

Wear Resistant

Contains V-trimmed side wires made out of platinum which prevents wear.

Constructional Benefit

Made according to OE equivalent structure which is suitable for each and every engine.

Greater Ignition

The core electrode is mainly 0.6 mm fine wire made of iridium enriched platinum alloy, assisting in proper ignition of fuel and better performance of the vehicle.

Pros

• Better durability.
• Have attached motor sit.
• Guaranteed for seven years.

Cons

• Difficult to gap.

4. NGK (3459) ZFR5N V-Power Spark Plug

Approved by Original Equipment Manufacturer (OEM), NGK (3459) ZFR5N V-Power Spark Plug is an impressive upgrade from typical spark plugs. If you are thinking of getting an NGK spark plug, you should definitely go with this model. Unique V-groove in the central electrode creates a spark between the central electrode and the ground electrode, which specifically helps in fuel ignition.

The central electrode V-groove makes it possible for the flame to expand to more regions; increasing ignitability which also results in a smooth and pleasant ride. After all, it is Best for jeep wrangler tj and jeep Cherokee.

Features and Benefits

Good Quality Construction

Very simple in design but built according to OEM specifications, so surely can rely on NGK (3459) ZFR5N V-Power Spark Plug for higher quality.

Long Term Durability

Metal plate made out of trivalent material, resistant to corrosion and abrasion which in terms provides durability for a longer lifespan.

Longer Lifespan

NGK (3459) ZFR5N V-Power Spark Plug reduces the voltage specifications of the ignition system and guarantees longevity.

Pros

• Resistant to corrosion.
• Very easy installation.
• Highly resilient for chemical and electrical wear.
• Triple seals avoid leaks.
• Higher fuel efficiency and decreased emission.

Cons

• Relatively costly than traditional spark plugs.

5. Champion Copper Plus Spark Plug

Champion Copper Plus Spark Plug is commonly used today in a number of applications for power equipment. The nickel central electrode containing copper core lowers the firing pin’s operating temperature and offers a service life of up to 12,000 miles or 20,000 kilometers.

So you are guaranteed unlimited mileage for at least two years. You can use it in marine, small engine, automotive vehicles. It is also regarded as the best spark plug for jeep wrangler jk. Sometimes also used in non-automotive operations, like a garden, lawn, and other equipment.

Features and Benefits

Corrosion Resistant

Champion Copper Plus Spark Plug provides more efficient performance. The shell of the spark plug is covered with a Protected Ultraseal, making it extra resistant to corrosion.

Smooth Action

Platinum ground electrode and central fine wire electrode (platinum) with special heat-active material assists the spark plug to easily achieve optimum temperatures and sustain steady working temperature; improving vehicle efficiency. So you are set for a smoother ride.

Standard Structure

These 4 x 1 x 1-inch spark plugs are built according to SAE and ISO standards, which stand for improved performance. Also, they have a semiconductor resistor of Patented SAC-9 for final suppression.

Pros

• Have a longer life.
• Maximum durability.
• Effective wear properties.

Cons

• May face problems while stalling.

6. E3 Spark Plugs E3.58 Automotive Spark Plug

Looking for the best spark plugs for 4.0 jeep Cherokee? Then E3 Spark Plugs E3.58 Automotive Spark Plug is the right choice for you. These spark plugs assist the engines to perform more efficiently with smoother, faster acceleration.

The precise central electrode along with special ground electrode assures optimum performance for five years or in other terms for 100,000 miles.

Features and Benefits

Patented Application

Uses three legs to secure the DiamondFire electrode to the spark plug shell assuring proper heat transfer and improve the cylinder turbulence.

Superior Durability

Yttrium-enriched alloy lessens the sideware temperature up to 8% resulting in lower pre-ignition. Also, the performance of the spark plug is enhanced as it is modeled with cooler heat ranges.

Beneficial Design

Has a thread dia of 14mm, hex size of 5/8 inch, and reach plug of 0.75-inch containing a gasket seat often can be used for different operations, mostly used in jeeps.

Pros

• Increased fuel efficiency.
• Elevated life span.
• Lower fuel consumption and higher power.
• Reduced toxic emission.

Cons

• Cannot adjust the gaps.

How to Choose Best Spark Plug for 4.0 Jeep Wrangler?

You can find various kinds of working spark plugs in local stores. But it can be difficult finding the best spark plug for your 4.0 jeep wrangler.

So it is really essential to know some factors before buying spark plugs for your 4.0 jeep wrangler. Check out the following factors:

• Material

It is crucial to analyze which material perfectly fits your needs when you purchase spark plugs. Copper is desirable for vehicles of an older model that have distribution based ignition with low voltage.

On the other hand, Platinum and Iridium are ideal for the latest engines. Platinum provides a mix of longevity and great performance, where Iridium provides a better mix but a bit expensive.

• Heat Span

A spark plug generally is called “hot” when it has a stronger heat insulator and “cold” when it generates additional heat out from the tip and reduces its temperature.

Normally, manufacturing companies designate a spark plug’s heat span with something like a number. For significantly hotter plugs some companies choose ascending numbers and others do the reverse for colder plugs.

• Gap Design

Spark plugs usually contain a spark gap that can be changed while using a gaper tool for the spark plug. Even a single spark plug can be built for multiple different engines, each requiring a totally different gap. To find out the spark gap, you can choose a gap gauge to make sure that it is within the selected range.

• Thread Size

Another way to specify a spark plug is by their thread and nut size. A typical spark plug has thread size as follows: 10mm (with 16mm nut), 12mm (with 14mm, 16mm or 17.5mm nut), 14mm (with 16mm or 20.63mm nut), and 18mm (with 20.63mm nut).

What causes spark plugs to foul quickly?

If the engine of a vehicle is reluctant to proceed, it also means that the spark plugs may need change. Usually, most of the OE spark plugs have a longer lifecycle, because the electrodes include precious material like iridium and platinum. If the spark plugs fail earlier than the prescribed interval, prior to installing new plugs, it is really necessary to fix the issue.

Fouling of spark plugs can happen due to many reasons. Sometimes you see that your vehicle is not starting on the first attempt and then you try multiple times to start the engine. This leads to the flooding of the engine, which will drain the plugs in turn so that they will not create any type of spark to restart the engine.

Wet fouling can also occur due to a variety of mechanical failures. Another example is the leaking of a cold starter injector. It creates a dense start-up solution in the cylinder head that causes the fouling of plugs.

During combustion, most fuel oxidizes, creating carbon monoxide and carbon dioxide. The unburned carbon polymerizes into deposits of carbon until more fuel and lesser oxygen is available. These substances cling to the hotter zones of the ignition chamber which includes the tip as well as an insulator of the spark plug. Also if the oxygen sensor does not report accurately to the air coming to the engine, it can cause carbon foul to the spark plug by creating a rich-running status.

Sometimes damaged piston rings or excess cylinder wear frequently contribute to sparking plug fouling. Excessive fuel release in the engine compartment stops a spark even from developing during ignition.

How to remove spark plugs with regular socket?

Don’t have a spark plug socket for removing your spark plug? Don’t worry, you can easily use your regular socket. All you need to do is follow these steps.

First, you need to figure out the location of your spark plugs. Most of the cars have them in engine front in a row, except some old modeled V-engines. Make sure to cool down the engine before you start. If you cannot find the spark plugs check all over the engine for some black rubber wire and spark plugs will be at the end of the wire. Some engines have the plugs covered, in that case, remove it. Otherwise, just check the manual of the car.

Next, you need to do is get your tools and equipment ready. Loosen the spark plugs any non-spark plug socket wrench. After that, grab some strong magnets equivalent to the plug size and stick them to the end of the wrench. Take that end to the tip of the plug and the magnets will grab the spark plugs, thus you can remove them and replace them with new plugs.

What to do after changing spark plugs?

After changing spark plugs check if the plugs are set according to the specified gap, if not, then fix them. Secondly, make sure you got the right plugs for your jeep. Thirdly, have the wires checked out. All of the wires need to be hooked up correctly.

Finally clean around the plug area. When you remove the plug, any kind of dirt that was built around the plug would slide into the cylinder. Nothing can go into those gaps when the plugs are removed. Compressed air can be used for blowing away the dirt across the plug area or use rubbing alcohol in case of heavy buildup of dirt. Before installing new plugs, you must make sure those holes are clean.

FAQ

Q: How often to change spark plugs Jeep Wrangler?

Answer: That truly relies on the spark plugs quality that you use in your vehicle. Obviously, spark plugs of higher quality would last longer than the ones with lower quality. Most of the mechanics suggest that jeep 4.0 spark plug replacements should be done each 30,000 miles for spark plugs with copper core and every 50,000 miles with iridium core. This period may be relatively short if your vehicle engine is not in peak condition. So, do check your plugs for unnecessary wear and replace them accordingly.

Q: Can I drive my truck with a missing spark plug?

Answer: Can you drive? Yes, you can. Should you? No, absolutely not.

In a single-cylinder petrol engine, the engine won’t start with a missing plug, because without that spark plug the car will not be able to convert the fuel’s chemical energy into heat to drive the car. In a multi-cylinder engine, you can drive your truck with a missing plug, but the thing is that in its intake stroke, it breathes some uncertain amount of explosive fuel-air mixture and releases that with an ignition spark in the atmosphere underneath your hood. So, it is best not to drive your truck with a missing spark plug.

Q: What types of spark plugs are compatible with Jeep Grand Cherokee 4.0L?

Answer: A resistor with copper core type spark plugs is best fitted for Jeep Grand Cherokee 4.0L. Various spark plugs fall into this category. The Jeep Wrangler Grand Cherokee (set of six) Spark Plugs really goes flawlessly with this model. The 6-Piece NGK V-Power Spark Plugs fits well in older jeeps. The Autolite XP985-4K Iridium XP Spark Plug is another best option. The NGK (3459) ZFR5N operates with a wide variety of Jeep Grand Cherokee 4.0L models as it is built according to OEM specifications. You can also use the Champion RC12LYC (412) Copper Plus Spark Plug as a proper replacement for your Jeep Cherokee 4.0L. So, you can see different types of spark plugs can be used in Jeep Grand Cherokee 4.0L.

Q: Jeep wrangler spark plug replacement cost.

Answer: jeep wrangler 4.0 spark plug replacement is needed to be done when the plugs are severely damaged or cannot be used anymore. For this, you need full information about the cost of spark plug replacement. The average cost falls between $275-$323, which include labor cost between $165-$194, and the cost of the parts between $110-$129.

Final Words

As you can see, the spark plug plays a vital role in a vehicle’s smooth operation. If one or more spark plugs get damaged or goes missing, the vehicle would make noise or other problems.

On the other hand, you must use the appropriate plug that is specified for your vehicle, otherwise, it will not perform the way it is expected.

Among all the spark plugs review, Bosch Double Iridium Spark Plug seems to fulfill all the demands. Its double iridium plugs provide longevity, it has great durability and excellent ignitability. But in the end, it’s actually you who gets to decide which will be the best spark plugs for 4.0 jeep.

Happy Driving.