2025 Guide: Best Spark Plugs For Mercedes GL450 Ranked

When I first tackled the routine maintenance on my Mercedes GL450 V8, I realized how critical the right spark plugs are for maintaining that smooth, German-engineered power. Replacing them is a straightforward job, but choosing the correct set can drastically impact your engine performance, fuel economy, and cold starts. In this guide, I’ve broken down the best spark plugs for mercedes gl450 models (specifically the 4.7L M273 engine) to help you pick the set that keeps your luxury SUV running like new.

IMAGE	PRODUCT NAME	AMAZON LINK
	8 pc NGK Iridium IX Spark Plugs compatible with…	View on Amazon
	95983 Double Iridium Spark Plug Compatible with…	View on Amazon
	A-Premium Iridium Platinum Spark Plugs Compatible with…	View on Amazon
	UF535 Ignition Coils Pack & Iridium Spark Plugs 4.7L 5.5L…	View on Amazon
	SYKRSS 93911 Iridium Platinum Spark Plugs 8 Pack -…	View on Amazon

8 pc NGK Iridium IX Spark Plugs compatible with Mercedes-Benz GL450 4.6L 4.7L V8 2007-2012

NGK is practically synonymous with quality ignition components, and their Iridium IX line is a gold standard for luxury vehicles like the GL450. This 8-pack is a direct replacement for 2007-2012 V8 models, ensuring excellent fitment and OE-level performance. The fine wire iridium tip provides a consistently strong spark, which translates into smoother idle and noticeable throttle response. These are the plugs you install when you want reliability and performance without compromise.

Key features that stand out:
– Iridium Construction: Provides extreme durability and efficient, concentrated spark.
– Genuine NGK Parts: Assurance of quality and precision engineering.
– Direct Replacement: Designed specifically for the Mercedes-Benz GL450 4.7L V8 engine.

Pros:
– Industry-leading quality and reliability
– Enhances cold starting performance
– Exceptional lifespan for an Iridium plug
– Perfect OEM fitment confirmed

Cons:
– Can be slightly more expensive than generic aftermarket options.

Best for: Drivers seeking premium, OE-quality performance and long-term reliability for their GL450.

Expert Opinion: NGK Iridium is frequently recommended by Mercedes mechanics globally because it consistently performs well in the high heat demands of the M273 V8 engine.

95983 Double Iridium Spark Plug Compatible with MERCEDES-BENZ C250 C300 C350 CL550 CLK350 CLS550 E300 GL450 GL550 ML350 ML450 S350 S400 S450 Dodge Sprinter Set of 6

This double iridium option is engineered specifically for maximum longevity, boasting a potential working life of up to 100,000 kilometers. The double iridium design means both the center electrode and the ground electrode are fortified with the precious metal, significantly reducing gap erosion over time. If you often experience weak acceleration or rough idling due to older components, this set provides the consistent, stable spark necessary for superior cold-start performance and better fuel economy.

Key features that stand out:
– Double Iridium: Extended service life and consistent performance.
– Better Fuel Economy: Improved combustion efficiency helps reduce consumption.
– Wide Fitment Range: Compatible with numerous Mercedes V6 and V8 engines (but double-check quantity needed).

Pros:
– Outstanding longevity and wear resistance
– Consistent and stable ignition performance
– Excellent value for the lifespan offered

Cons:
– Only comes as a set of 6, meaning GL450 V8 owners must buy two sets (12 plugs) to complete the job.

Best for: High-mileage drivers who prioritize the longest possible service intervals between replacements.

Expert Opinion: While the longevity of double iridium is attractive, buyers must be aware that the GL450 V8 requires eight spark plugs, so budgeting for multiple packs is necessary.

A-Premium Iridium Platinum Spark Plugs Compatible with Mercedes-Benz CL550, CLK550, CLS550, E550, GL450, GL550, G550, ML550, S450, S550, SL550, R550, 4.7L 5.5L, Pack of 8

A-Premium offers a robust hybrid option, combining an Iridium center electrode with a Platinum core, designed to balance performance and durability perfectly. This pack of 8 is designed specifically for the V8 Mercedes engines, including the GL450 4.7L, ensuring you have the exact number required for a complete job. Engineered to meet or exceed OEM specifications, these plugs deliver exceptional ignitability, promoting fast starts and maintaining peak engine performance throughout their recommended 80,000 to 100,000-mile service life.

Key features that stand out:
– Hybrid Construction: Iridium tip for superior spark; Platinum core for heat dissipation and endurance.
– Engineered for Longevity: Recommended replacement interval is 80,000 to 100,000 miles.
– Standardized Specs: Includes resistance, gap size, and thread diameter details for technical assurance.

Pros:
– Strong performance/durability balance
– Sold in the correct 8-pack quantity for the GL450
– Excellent longevity potential

Cons:
– Brand reputation is newer compared to industry giants like NGK or Bosch.

Best for: Budget-conscious buyers who want long-life Iridium/Platinum technology in the correct 8-pack quantity.

Expert Opinion: The detailed specifications provided by A-Premium are a strong indicator of quality control. For many drivers, this mix of Iridium and Platinum offers the ideal sweet spot for M273 engine maintenance.

UF535 Ignition Coils Pack & Iridium Spark Plugs 4.7L 5.5L Compatible with Mercedes-Benz CL550 CLK550 CLS550 E550 G550 GL450 GL550 S500 S550 SL550 2007 2008 2009 2010 2011 2012 2013 2014 2015, 8PCS

If your GL450 is reaching higher mileage (over 100,000 miles), you might notice symptoms like misfires that aren’t just spark plug related—they could be failing ignition coils. This comprehensive kit addresses both issues simultaneously, providing 8 Iridium spark plugs and 8 UF535 compatible ignition coils. By replacing the entire ignition system, you ensure optimal engine health, stable high-voltage output, and significant improvement in fuel combustion. This is the ultimate “reset” button for the ignition system.

Key features that stand out:
– 2-in-1 Complete Kit: Includes all 8 plugs and 8 ignition coils needed for a full V8 service.
– Superior Performance: Focuses on enhancing ignition efficiency and engine power.
– High-Quality Materials: Coils feature durable copper windings and robust ceramic insulators for heat resistance.

Pros:
– Ideal for high-mileage engine tune-ups
– Excellent value considering coils are included
– Simplifies the maintenance process (one purchase)

Cons:
– If your existing coils are perfectly fine, this kit provides unnecessary parts.

Best for: High-mileage Mercedes GL450 owners experiencing misfires who need a complete ignition system overhaul.

Expert Opinion: While I typically prefer OE coils, purchasing a combined kit like this can save a tremendous amount of labor and cost if the vehicle is already showing intermittent ignition issues. It’s a proactive way to maintain the vehicle.

SYKRSS 93911 Iridium Platinum Spark Plugs 8 Pack – Compatible with Mercedes-Benz CL550, CLK550, CLS550, E550, GL450, GL550, G550, ML550, S450, S550, SL550, R550, C300, C350, C250 4.7L 5.5L Engine

SYKRSS provides another highly compatible Iridium Platinum option sold in the required 8-pack quantity for the GL450 V8 engine. What sets these apart is the focus on installation ease: they are pre-gapped to 0.7-0.8mm (0.028”-0.032”), which minimizes installation hassle and the risk of damaging the electrode gap. Crafted from temperature-resistant materials, these plugs are designed to meet or exceed OEM standards, guaranteeing a strong, consistent spark and maximizing engine power.

Key features that stand out:
– Pre-Gapped: Ready for installation right out of the box, reducing prep time.
– OE Replacement Standard: Meets or exceeds OEM specifications for fit and function.
– Strong Customer Support: Backed by a 1-year repair and replacement service.

Pros:
– Installation is fast and simple due to pre-gapping
– Excellent fitment assurance
– Durable Iridium Platinum construction

Cons:
– The pre-gap still needs to be verified for specific engine tolerance, despite being advertised as ready-to-install.

Best for: DIYers who want a hassle-free installation process with high confidence in OE compatibility.

Expert Opinion: Pre-gapped plugs are a great convenience, but professionals will always verify the gap against the manufacturer’s specific settings, especially when installing the best spark plugs for mercedes gl450 to ensure optimal performance.

Comparison and Buying Insights

When you’re deciding between the best spark plugs for mercedes gl450, the choice often boils down to budget versus maintenance longevity.

The most traditional, high-quality choice is the NGK Iridium IX. While sometimes pricier, NGK has the reputation and manufacturing precision that makes it an immediate trusted replacement for the Mercedes M273 engine.

If you are looking strictly for mileage and want to forget about spark plugs for 100,000 miles, the Double Iridium 95983 is appealing due to its robust construction. However, remember the GL450 needs 8 plugs, so you’ll need two sets.

For the best value pack, the A-Premium and SYKRSS Iridium Platinum packs offer excellent longevity in the correct quantity of 8, without the high brand premium of NGK. The SYKRSS pre-gapped option is especially convenient for the weekend mechanic.

Finally, consider the UF535 Kit only if your GL450 is experiencing consistent misfires or you know your coils are original and nearing the end of their service life. Replacing coils and plugs together is preventative maintenance that saves on future labor costs.

Final Verdict: Our Top Picks

Choosing the right components for your luxury SUV shouldn’t be complicated. After evaluating performance, longevity, and overall value, here is how we rank the best spark plugs for your Mercedes GL450:

The Overall Winner (The Trusted Choice): The 8 pc NGK Iridium IX Spark Plugs takes the top spot. NGK consistently delivers reliable, high-performance sparks, which is crucial for the sophisticated M273 V8 engine. You pay a bit more, but you get guaranteed quality.

The Best Value for Longevity: The A-Premium Iridium Platinum Spark Plugs offer the ideal balance. They provide 80,000–100,000 miles of service life in the correct pack size, making them a highly cost-effective yet durable option.

The Best Maintenance Solution: For vehicles over 100,000 miles, the UF535 Ignition Coils Pack & Iridium Spark Plugs kit provides necessary peace of mind by completely refreshing the entire ignition system.

Best Spark Plugs For Mercedes GL450 FAQ

What are the main signs that my Mercedes GL450 needs new spark plugs?

Common symptoms include rough idling (the engine feels shaky while stopped), hesitation or poor acceleration, difficulty starting, and noticeable drops in fuel economy. In severe cases, the M273 engine might trigger a check engine light due to a persistent misfire code. Replacing the best spark plugs for mercedes gl450 can resolve these issues quickly.

How often should I replace the spark plugs in my GL450 (M273 V8 engine)?

Mercedes-Benz typically recommends replacing spark plugs on the M273 engine between 60,000 and 80,000 miles. While many modern Iridium or Platinum plugs are rated for up to 100,000 miles, it’s advisable to stick closer to the 80,000-mile mark for optimal performance in high-performance V8 engines.

Does the Mercedes GL450 (4.7L V8) require 6 or 8 spark plugs?

The GL450 uses a V8 engine (the M273), which has eight cylinders. Therefore, you must purchase a set of eight spark plugs for a complete replacement. If you buy a set of six, you will have to order more to finish the job.

Is it necessary to replace the ignition coils when I replace the spark plugs?

Not always, but it’s highly recommended, especially on higher-mileage GL450s (over 100,000 miles). Ignition coils have a similar service life to spark plugs, and a failing coil can quickly damage a new plug. If you notice persistent engine misfires, purchasing a comprehensive coil pack and spark plug kit is the most economical solution.

Do I need to gap Iridium spark plugs before installing them in my GL450?

While many manufacturers (like SYKRSS) advertise their plugs as “pre-gapped,” you should always verify the gap with a proper spark plug gap tool against the Mercedes-Benz manufacturer specification. Iridium tips are delicate, and handling them carefully is essential to prevent damage.

What is the advantage of Iridium over standard Copper or Platinum plugs for the Mercedes V8?

Iridium is one of the hardest and densest materials used in spark plugs. It allows for a smaller center electrode, which provides a more focused and stable spark. For the high heat and compression of the GL450’s M273 V8, Iridium offers superior durability and maintains the correct gap for a significantly longer period than copper or standard platinum plugs.