A Guide to Spark Plugs for the 2000-2008 Jaguar S-Type
Keep your S-Type's V6 or V8 engine running smoothly with the correct new aftermarket spark plugs.
- Stick with Iridium or Platinum plugs from top-tier brands like NGK or Denso for the best performance and longevity.
- On 3.0L V6 models, replacing all six plugs requires removing the intake manifold, which adds significant time and complexity.
- Check for oil in the spark plug wells; if found, you must also replace the valve cover gaskets.
- Do not attempt to gap modern Iridium or Platinum spark plugs, as you can easily damage the fragile electrode.
Signs of Failing Spark Plugs
When your S-Type's spark plugs start to wear out, you'll likely notice. The engine's computer is sensitive to ignition problems and will often trigger the Check Engine Light. Look for these common symptoms:
- Rough Idling: The engine may shake or vibrate more than usual when you're stopped.
- Engine Misfires: You might feel a hesitation or stumble during acceleration. A flashing Check Engine Light often indicates a misfire.
- Reduced Power: Your Jaguar may feel sluggish and less responsive than it used to be.
- Poor Fuel Economy: Worn plugs can't burn fuel efficiently, leading to more frequent trips to the gas station.
- Difficulty Starting: While other issues can cause hard starts, worn-out spark plugs can be a contributing factor.
A Common Issue: Oil in Spark Plug Wells
A well-documented issue on the S-Type, particularly the 4.0L V8, is failing valve cover gaskets. This allows engine oil to leak into the spark plug wells, saturating the ignition coils and spark plugs. If you find oil when changing your plugs, you must replace the valve cover gaskets to solve the root problem. Simply cleaning the oil away is a temporary fix, and the misfires will return. There is a Technical Service Bulletin (TSB S303-14) related to diagnosing engine management issues, which can be caused by problems like this.
Choosing the Right Aftermarket Spark Plugs
Jaguar originally used high-quality, long-life spark plugs, typically made of platinum or iridium. When choosing a replacement, it's best to stick with these materials for longevity and performance. Cheaper copper plugs will not last as long and may reduce performance.
Here’s a breakdown of the brands available in our inventory:
| Brand Tier | Brands | Quality & Performance Assessment |
|---|---|---|
| Top Tier (OEM & Exceeds OEM) | NGK, Denso | NGK was the Original Equipment Manufacturer (OEM) for many S-Types. Both NGK and Denso are highly recommended by Jaguar owners and mechanics for their reliability, performance, and long life. Iridium plugs from these brands are considered an excellent choice. |
| Mid-Tier (Solid Performer) | Bosch | Bosch is a trusted brand that produces quality spark plugs, including double platinum and iridium options that are a good fit for the S-Type. They offer reliable performance and efficient combustion. |
| Economy Tier | Autolite, Champion | These brands offer more budget-friendly options, including platinum and copper plugs. While functional, they may not offer the same longevity or refined performance as the top-tier brands in a European engine like the Jaguar's. |
| Budget | Skyward | This is a value-oriented brand. Expect basic performance and a shorter lifespan compared to premium options. Best for those on a tight budget who don't mind more frequent changes. |
Pro Tip: Pre-Gapped Plugs
Most modern iridium and platinum spark plugs come pre-gapped from the factory. It is critical not to attempt to gap them yourself, as the fine-wire electrodes are extremely fragile and can be easily damaged. Always verify the part number is correct for your specific S-Type engine (3.0L V6, 4.0L V8, or 4.2L V8) to ensure you get the correct pre-set gap.
Frequently Asked Questions
How often should I replace the spark plugs on my S-Type?
The original recommendation is typically between 60,000 and 100,000 miles for platinum or iridium plugs. However, if you notice any failure symptoms, you should inspect them sooner.
Is it difficult to replace the spark plugs myself?
It depends on your engine. On the 3.0L V6, one bank of cylinders is easy to access, but the other is located under the intake manifold, which must be removed 🎬 See how to remove the intake manifold on V6 models.. This makes the job significantly more complex. On V8 models, the rearmost plugs (cylinders 7 and 8) can be very difficult to access due to limited space near the firewall 🎬 Learn how to access difficult spark plugs on V8 engines.. While DIY is possible, it can be challenging.
Should I replace the ignition coils at the same time?
It's a good practice, especially on higher-mileage vehicles or if you're already removing the intake manifold on a V6. An aging coil can cause a new plug to perform poorly. If you found oil in the plug wells, it is highly recommended to replace the oil-soaked coils.
What is the difference between Platinum and Iridium spark plugs?
Both are long-life materials. Iridium is a harder and more durable material than platinum, with a higher melting point. This allows for an even finer-wire center electrode, which can improve ignitability and performance. For the S-Type, both are excellent choices, but Iridium is generally considered the premium option.
Helpful Videos
Technical Specifications
OEM Part Numbers: C2S46895 C2A1535 AJ84575
The correct spark plug depends on your engine (3.0L V6, 4.0L V8, 4.2L V8, or 4.2L Supercharged V8). Always use your vehicle's information to confirm fitment. Most require a 16mm or 5/8" spark plug socket. The recommended material is Iridium or Platinum.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Jaguar S-Type: