A Guide to Replacing Ignition Coils on Your 2012-2019 Audi S8 4.0T
Understanding ignition coil failure is key to keeping your S8's twin-turbo V8 running smoothly.
- Ignition coil failure is a common issue on the S8's 4.0T engine, causing misfires, rough idle, and a check engine light.
- It is strongly recommended to replace all eight coils and spark plugs at the same time to ensure reliability and prevent future failures.
- Stick with high-quality OE-supplier brands like Bosch or NGK for the best performance and longevity on this high-output engine.
- A flashing check engine light indicates a severe misfire; pull over immediately to prevent expensive damage to your catalytic converters.
Symptoms of a Failing Ignition Coil
Ignition coil failure is a common issue on many Audi engines, including the 4.0T V8 in your S8. When a coil starts to fail, it can't produce the strong spark needed for proper combustion. This leads to several noticeable problems. The most common sign is a Check Engine Light, often accompanied by engine misfires. You might feel the engine running rough, shaking, or hesitating when you accelerate. Other symptoms include a loss of power, reduced fuel economy, and in some cases, a smell of gasoline from the exhaust because unburned fuel is passing through the engine. If the Check Engine Light is flashing, it's a sign of a severe misfire that could damage your expensive catalytic converters. In this case, you should stop driving immediately.
Misfire Codes Aren't Always a Bad Coil
While a misfire code like P0301 (Cylinder 1 Misfire) often points to a bad coil or spark plug, it's not always the case. On the 4.0T engine, a persistent misfire that doesn't resolve after swapping coils could indicate more serious issues like a faulty fuel injector or even internal engine problems. One Audi Technical Service Bulletin (TSB) notes that random misfire codes (P0300) can sometimes be caused by corrosion on cylinder walls, which requires professional diagnosis.
🎬 Watch: A professional diagnosis of a complex S8 misfire.Choosing the Right Aftermarket Ignition Coil
When replacing ignition coils on a high-performance vehicle like the S8, quality matters. While OEM coils from an Audi dealer are a guaranteed fit, high-quality aftermarket options can provide the same performance for less money. It's best to stick with brands known for being Original Equipment (OE) suppliers to Audi and other German manufacturers.
Tier 1: OE-Quality Brands
These brands are often the original manufacturers for Audi and offer the best quality and reliability. They are a safe and recommended choice for the S8.
- Bosch: A very common OE supplier for Audi. Bosch coils are widely trusted and considered a direct equivalent to the genuine Audi part.
- NGK: Another top-tier brand known for its high-quality ignition components. NGK is a popular choice among enthusiasts and is known for its durability and performance.
Tier 2: Reputable Aftermarket Brands
These brands are well-known in the aftermarket and offer a good balance of quality and price. They are generally reliable for daily driving.
- Delphi: A major OE supplier for many car brands, Delphi makes reliable ignition coils that are a popular aftermarket choice. Some users note minor differences in the fit of the rubber boot compared to the original part, but they generally perform well.
- Standard Ignition (SMP): A long-standing aftermarket manufacturer that produces a wide range of quality parts.
- Walker Products: Known for engine management and fuel system components, offering reliable aftermarket options.
Tier 3: Economy Brands
While more affordable, the long-term reliability of these brands on a high-output engine like the S8's 4.0T is less certain. For a vehicle of this caliber, it's generally recommended to invest in a Tier 1 or Tier 2 brand.
- DriveWire
- Global Parts
Replace in Sets
It is highly recommended to replace all eight ignition coils at the same time, especially if your vehicle is over 60,000 miles. Coils are subjected to the same heat and wear, so if one fails, others are likely to follow. Replacing them all at once saves you from repeated repairs in the near future.
🎬 See this step-by-step DIY guide for replacing coils and plugs.Cost to Replace Audi S8 Ignition Coils
| Part Type | Cost (Set of 8) |
|---|---|
| New OEM (Dealer) | $550 - $720 |
| New Aftermarket (Tier 1) | $320 - $620 |
| Shop Labor | $250 - $500 |
Frequently Asked Questions
Is a special tool needed to remove the ignition coils?
Generally, no. While some VW/Audi engines use a special puller, the coils on the 4.0T V8 can usually be removed by hand after unbolting them. If they are stuck, a gentle pry with a plastic trim tool can help. The main tools needed are a T30 Torx socket and basic hand tools.
Should I replace my spark plugs at the same time?
Yes, it is highly recommended. Worn spark plugs put extra strain on the ignition coils, which can cause them to fail prematurely. Since accessing the coils requires some labor, replacing the spark plugs at the same time is efficient and good preventative maintenance.
Were there any recalls for the 2012-2019 Audi S8 ignition coils?
No, there have been no specific recalls issued by the NHTSA for ignition coil failure on the 2012-2019 Audi S8. There were recalls for potential fuel leaks and an engine compartment seal, but not for the coils themselves.
How difficult is it to replace the ignition coils myself?
For a DIY mechanic with some experience, it is a manageable job. However, it is more complex than on simpler engines. Accessing the coils requires removing engine covers and carefully moving wiring harnesses out of the way. The driver's side can be particularly tight. Expect the job to take 2-4 hours.
🎬 Watch: A complete walkthrough of the 4.0T coil pack installation.Helpful Videos
Technical Specifications
OEM Part Numbers: 079905110P 079905110N 079905110L 079905110K 079905110H
This vehicle uses a coil-on-plug ignition system with one coil per cylinder, for a total of eight coils.
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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.
- Audi S8:
- 🎬 Helpful Videos
- 🛍️ Shop This Part
- Symptoms of a Failing Ignition Coil
- Misfire Codes Aren't Always a Bad Coil
- Choosing the Right Aftermarket Ignition Coil
- Tier 1: OE-Quality Brands
- Tier 2: Reputable Aftermarket Brands
- Tier 3: Economy Brands
- Replace in Sets
- Cost to Replace Audi S8 Ignition Coils
- Frequently Asked Questions
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