Replacing Spark Plugs on a Nissan Murano: A Complete Guide

Crossover operation Nissan Murano with a VQ series gasoline engine requires regular maintenance, where the ignition system plays a special role. Timely replacement of spark plugs allows you to maintain optimal dynamics, reduce fuel consumption and avoid problems with starting a cold engine. Many owners believe that the service life of spark plugs is 100 thousand kilometers, but the reality is often different, especially in city traffic jams.

Engine specifics VQ35DE or VQ35HR (depending on the year of manufacture) is such that access to the spark plugs is difficult due to the design of the intake manifold. This makes the procedure a more complex task compared to conventional 4-cylinder engines. Incorrect selection of tools or haste can lead to damage to the ceramic insulator or breakage of the threads in the cylinder head.

Choosing the Right Spark Plugs for your Murano

The choice of spark plugs is the foundation for reliable engine operation. Nissan Murano. The manufacturer recommends using original products with iridium coating, which provide a stable spark under high loads and pressure in the combustion chamber.

The original part number for most models with a 3.5 liter engine looks like 22401-ED00A or 22401-1AA0A. However, there are also high-quality analogues from the world's leading manufacturers, which often surpass the original in terms of service life or cost.

• 🔥 NGK - Market leader, often supplied as an OEM supplier to Nissan, excellent spark stability.
• 💎 Iridium Power - a series from NGK with a thinner electrode, providing better flammability.
• ⚙️ DENSO is a reliable Japanese brand that offers excellent alternatives with a long service life.

You should not save on this element, since cheap spark plugs with copper plating may require replacement after 20-30 thousand kilometers, which, given difficult access to them, increases the cost of maintenance. Using non-standard spark plugs with the wrong heat rating can lead to overheating or detonation.

⚠️ Attention: Never install spark plugs with a gap of more than 1.1 mm on engines VQ35DE without flashing the ECU, as this can cause misfires and damage to the catalyst.

When purchasing, be sure to check the packaging for holograms and compliance with the labeling. Counterfeiting is quite common in this area, and it can be difficult to visually distinguish an original from a replica without a microscope.

Necessary tools and preparation

Before you begin dismantling, you need to prepare a working kit. Not having the right tool at the most crucial moment can leave you with a disassembled car and a broken key. Pay special attention to extensions and universal joints, as access to the rear spark plugs is extremely limited.

You will need a set of drive heads 1/2 or 1/4 inches. For the candles themselves, a head on 16 mm (less often 5/8 inch, but on modern Murano this is exactly 16 mm). Be sure to have a magnetic extension or candle holder to prevent it from falling into a deep well.

• 🛠️ Candle head 16 mm with a rubber holder inside.
• 🔧 Long extension (minimum 250-300 mm) for access to the rear cylinders.
• 🌀 Cardan joint (flexible shaft) for easy twisting.

You also cannot do without a torque wrench. The tightening of spark plugs on Nissan engines has strict standards, violation of which can result in gasket deformation or thread breakage. For VQ series motors the tightening torque is typically 13-15 Nm.

Also have a can of penetrating lubricant (WD-40 or equivalent) and an air compressor ready. Before unscrewing the spark plug, it is necessary to blow out dust from the well, otherwise it will get into the cylinder and scratch the walls of the liner.

⚠️ Warning: If you use graphite lubricant on the spark plug threads, make sure it is compatible with high temperatures, otherwise it may turn into carbon and make it difficult to unscrew next time.

Removing the intake manifold

The main feature of replacing spark plugs with Nissan Murano — the need to remove the intake manifold. This is not a whim of mechanics, but a design necessity, since the front and rear spark plugs are covered by a plastic “labyrinth” of air distribution. The removal process requires care and patience.

First you need to remove the decorative plastic engine cover by snapping the latches. Next, the crankcase ventilation hoses, vacuum system tubes and sensor connectors located on the manifold are disconnected. All connectors should be labeled or their location noted.

The bolts securing the manifold to the cylinder head are unscrewed. Usually there are several of them located around the perimeter. It is important to loosen them crosswise so as not to damage the gasket or the manifold housing, which is made of plastic and can crack if distorted.

• 🔩 We unscrew the manifold mounting bolts at the moment of loosening, and not immediately unscrewing.
• 🌬️ Disconnect all vacuum hoses and electrical connectors of sensors (mass air flow sensor, throttle position sensor).
• 🚫 Do not pull the collector towards you by force; if it is “stuck” - carefully pry it off with a screwdriver.

What to do if the collector is stuck?

If the manifold does not come off after removing all bolts, do not use excessive force. Try gently rocking it to the sides or using a penetrating lubricant at the joint. Sometimes heating the plastic with a hairdryer helps, but do it very carefully so as not to melt the parts.

After removing the manifold, access to all six spark plugs will open. At this point, it is important to protect the open intake ports from dirt and debris. Cover them with a clean rag or a special plug until the work is completed.

Spark plug replacement process

Now that access is open, you can move on to the main task. First you need to disconnect the ignition coils. They are fastened with bolts, which often stick or have a Phillips head, which requires a high-quality bit set. Gently pull the coil up without tugging on the wire.

Before unscrewing the spark plug, be sure to blow out the well with compressed air. Dust that has accumulated around the spark plug over years of use may fall into the cylinder when unscrewed. This is a critical error that can lead to scuffing of the liner and costly engine repairs.

Unscrew the spark plug slowly and smoothly. If the spark plug is screwed in tightly, do not try to yank it out of place - use lubricant and give it time to penetrate the thread. When unscrewing, monitor the condition of the ceramic insulator so as not to crack it if distorted.

• 🧹 Blow out the well with compressed air before each twisting of the candle.
• 🔩 Unscrew the spark plug smoothly, controlling the force on the key.
• 🔍 Inspect the old spark plug: the color of the soot will tell you about the condition of the engine (white, gray, black, oil soot).

Installing a new spark plug requires compliance with the tightening torque. If you don't have a torque wrench, hand-tighten the spark plug as far as it will go, then tighten it 1/4 or 1/2 turn with the wrench (depending on whether you have an O-ring). But it is best to use the tool for accuracy.

After installing the spark plugs, replace the ignition coils. Make sure they click and fit snugly against the candle. Tighten the coil mounting bolts to the recommended torque, usually 8-10 Nm so as not to strip the threads in the aluminum cylinder head.

Intake manifold installation and final check

Assembly is in reverse order but requires attention to detail. Before installing the manifold, be sure to check the condition of the gasket. If the gasket is old, cracked or deformed, it must be replaced, otherwise the engine will “trouble” and suck in excess air.

When tightening the manifold bolts, use a center-out pattern and a criss-cross pattern. This will ensure that the gasket fits evenly. The manifold bolt tightening torque is usually approx. 10-12 Nm, but it’s better to check the manual for your specific modification.

Connect all vacuum hoses and electrical connectors. Double-check each connection: a missing hose can cause an idle speed fault or loss of power. Install the decorative engine cover and secure it with clips.

Parameter	Meaning	Note
Spark plug tightening torque	13-15 Nm	Strictly using a torque wrench
Coil tightening torque	8-10 Nm	Do not overtighten, thread in aluminum
Manifold tightening torque	10-12 Nm	Crisscross from center
Spark plug gap	1.0-1.1 mm	Check before installation

After assembly, you need to start the engine and let it idle. Listen to the engine: it should run smoothly, without skipping or vibration. Check for errors on the dashboard.

⚠️ Attention: If you hear a whistle or hissing sound after starting the engine, turn off the engine immediately. Most likely, the intake manifold gasket is installed incorrectly or the bolts are not tightened evenly, which leads to air leaks.

Common mistakes and how to avoid them

Many owners Nissan Murano encounter problems after replacing spark plugs on their own. The most common mistake is dirt getting into the cylinders. This occurs due to neglect of purging the wells before unscrewing. Even a microscopic particle of sand can become an abrasive for the cylinder walls.

The second common problem is overtightening of spark plugs or coils. The aluminum cylinder head is soft and the threads there are easily stripped. If you feel that the bolt is tight, it is better to stop and check the torque with a wrench than to try to “finish” it until it stops.

• 🚫 Do not use lubricant on the spark plug electrodes - this will lead to an unstable spark.
• 🚫 Do not tighten the manifold bolts by hand without a torque wrench.
• 🚫 Do not ignore the condition of the vacuum hoses - old rubber may crack.

It's also worth mentioning replacing the manifold gasket. If you've removed the manifold for the first time in years, the old gasket may be falling apart. It makes sense to buy a new gasket in advance and change it with each procedure to avoid repeated dismantling.

Symptoms of spark plug wear

Knowing when it's time to change your spark plugs is just as important as knowing how to change them. Engine VQ35 quite sensitive to the state of the ignition system. The first sign of wear may be an increase in fuel consumption while maintaining the same driving style.

Another symptom is loss of acceleration dynamics and the appearance of vibrations at idle. If the engine begins to "trouble" or run unevenly, especially during a cold start, this is a sure sign of problems with the spark plugs or coils.

Sometimes the indicator on the instrument panel lights up Check Engine. In the case of Nissan Murano this often indicates a misfire (error codes P0300-P0306). Do not ignore this error, as long-term driving with misfires can damage the catalyst, the replacement of which is very expensive.

Cost and timing of work

If you decide to entrust the replacement of spark plugs to specialists, it is worth considering that this work is labor-intensive. Unlike simple 4-cylinder engines, where replacement takes 30 minutes, Nissan Murano it can last from 1.5 to 3 hours depending on the qualifications of the master and the availability of tools.

The cost of service work is usually higher than the market average due to the need to remove the intake manifold. However, if you have plumbing skills and the right tools, replacing them yourself will save you a significant amount by purchasing spark plugs in an online store at retail prices.

How long does the work actually take?

For an experienced technician with the correct set of heads and universal joints, the replacement takes about 1 hour. A beginner may need 2-3 hours, especially at the stage of unscrewing stuck manifold bolts.

Do not forget that the price of one candle in retail may differ from what the services offer. Purchasing a 6-pack directly from the manufacturer or major dealer is often cheaper than purchasing from a retail auto store.

FAQ: Frequently asked questions

Is it possible to change spark plugs without removing the intake manifold?

No, on engines VQ35DE and VQ35HR, installed on Nissan Murano, access to the spark plugs is completely blocked by the intake manifold. Without removing it, replacement is impossible.

Which spark plugs are better: iridium or platinum?

For engines Nissan Iridium spark plugs are recommended (for example, NGK Iridium IX). They provide a more stable spark and have a longer service life compared to their platinum counterparts, which is critical for highly boosted V6 engines.

What to do if the spark plug is stuck and cannot be unscrewed?

Do not use sudden jerks. Apply penetrating lubricant generously to the threads and allow time (15-20 minutes minimum). Try screwing the spark plug back in slightly to break off any corrosion, and then unscrew it. If that doesn't work, you'll need a professional tool to remove broken spark plugs.

Do I need to change the ignition coils along with the spark plugs?

It is optimal to change spark plugs every 60-80 thousand km, and coils every 100-120 thousand km or when errors occur. If the coils are working properly, it is not necessary to change them regularly along with the spark plugs, but it is recommended to check their condition.

How do you know which manifold gasket is needed?

The gasket depends on the year of manufacture and engine type. It is best to remove the old gasket (if it has not fallen apart) and select a new one according to its shape, or use the car's VIN code to order the original part in the catalog.