A Guide to Ignition Coils for the 2014-2016 BMW 435i
Keep your N55 engine running smoothly by understanding your ignition coil replacement options.
- For a stock 2014-2016 435i, use OEM-equivalent coils like Delphi or Bosch for best results.
- It is highly recommended to replace all six coils at once, especially if they are original and have high mileage.
- A failing ignition coil can cause expensive damage to your catalytic converters if ignored.
- This is a straightforward DIY job that can be completed in under two hours with basic tools.
Signs of a Failing Ignition Coil
Ignition coil failure is a common issue as these cars age. When a coil starts to go bad, it can't produce the strong spark your engine needs. This leads to noticeable problems. You should not ignore these signs, as a failing coil can lead to more expensive damage, particularly to the catalytic converters.
- Engine Misfires: This is the most common symptom. You may feel the engine shaking or sputtering, especially at idle or under acceleration. It can feel like a rough vibration.
- Check Engine Light: A misfire will almost always trigger the check engine light. A code reader will typically show codes from P0301 to P0306, which point to the specific cylinder that is misfiring. A P0300 code indicates a random or multiple cylinder misfire.
- Loss of Power: Your 435i will feel sluggish and won't accelerate as quickly as it should.
- Reduced Fuel Economy: When your engine isn't running efficiently due to a bad coil, your fuel consumption will increase.
- Stalling or Difficulty Starting: In severe cases, a complete coil failure can cause the engine to stall while driving or prevent it from starting at all.
Choosing the Right Aftermarket Ignition Coil
When replacing a coil, you have several options. For the 435i's N55 engine, sticking with brands that supply BMW directly is often the safest bet for reliability and fitment.
Tier 1: OEM & OEM-Equivalent Brands
These brands are known to be original equipment manufacturers for BMW. They offer the best fit and performance for a daily-driven vehicle without any modifications. Many owners and mechanics recommend using these brands to avoid issues.
- Delphi: Widely considered the primary OEM supplier for the N55 engine's ignition coils. BMW even issued a technical service bulletin (TSB) regarding cosmetic corrosion on Delphi coils, noting it doesn't affect performance. This is often the most recommended choice.
- Bosch: Another major OEM supplier for BMW. While some older Bosch coils had issues on other engines, their modern replacements are generally reliable. Ensure you get the correct part number for your vehicle.
- Eldor: Mentioned in forums as another high-quality OEM supplier for BMW, sometimes considered an upgrade over the standard parts for durability.
- NGK: While famous for spark plugs, NGK also produces high-quality ignition coils that are well-regarded in the BMW community.
Pro Tip: Replace in Sets
If one of your original ignition coils fails and your car has over 60,000 miles, it's a good idea to replace all six at once. Coils are wear-and-tear items and tend to fail around the same time. Replacing them all at once can save you from repeated repairs in the near future.
Tier 2: Performance Brands
For owners with tuned engines running higher boost, a performance coil kit might be a worthwhile upgrade to prevent misfires under high load.
- Precision Raceworks: Offers high-output ignition kits designed for tuned N55 engines to provide a stronger, more consistent spark.
- Mishimoto / Ignition Projects: These brands also offer performance-oriented coils that claim higher energy output for improved combustion, especially in modified cars.
Tier 3: Standard Aftermarket Brands
This category includes brands like DriveWire, Spectra, Standard Ignition, and Walker Products. These can be a cost-effective option, but quality and longevity can be inconsistent. They may be suitable for a quick repair on a budget, but for long-term peace of mind on a performance car like the 435i, an OEM-equivalent brand is generally recommended.
Known Issues & Bulletins
A Technical Service Bulletin (TSB SI B12 15 15) was issued in March 2015 for the N55 engine. It notes that moisture can get into the spark plug area and cause cosmetic corrosion on the metal sleeve of the Delphi ignition coils. BMW states that this does not impact the coil's performance, and they should not be replaced for this reason alone. No safety recalls have been issued by the NHTSA for ignition coils on the 2014-2016 BMW 435i.
Cost of Replacement
The cost can vary significantly based on the brand you choose and whether you do the work yourself.
| Item | Cost Range |
|---|---|
| Single OEM-Equivalent Coil (e.g., Bosch, Delphi) | $45 - $75 |
| Set of 6 OEM-Equivalent Coils | $270 - $450 |
| Single Budget Aftermarket Coil | $30 - $50 |
| Performance Coil Kit | $350 - $600+ |
| Shop Labor for all 6 Coils | $120 - $250 |
Frequently Asked Questions
Should I replace all six ignition coils at once?
It is highly recommended, especially if the vehicle has over 60,000 miles or if the coils are original. Ignition coils are subjected to the same amount of heat and wear, so when one fails, the others are likely not far behind. Replacing them all at once provides reliability and saves you from doing the same job multiple times.
Is it difficult to replace the ignition coils myself?
No, this is a very DIY-friendly job for the 435i. The difficulty is rated as easy. It involves removing the engine cover, a strut brace, and some plastic cowling to access all six coils. The coils themselves are held by a single connector and just pull out. The entire job can typically be done in 1-2 hours with basic tools.
What is the difference between Bosch and Delphi coils for my 435i?
Both are OEM suppliers to BMW. For the N55 engine in your 435i, Delphi is often the most recent and recommended part. Some earlier BMW models had issues with Bosch coils, leading BMW to switch to Delphi. However, modern versions from either brand should be reliable as long as you purchase from a reputable source.
Do I need to replace my spark plugs at the same time?
It's a great idea. You have to remove the ignition coils to get to the spark plugs anyway, so you will save on labor (or your own time) by doing both jobs at once. BMW recommends spark plug replacement around 60,000 miles. Worn spark plugs can also put extra strain on your new ignition coils, potentially causing them to fail prematurely.
Technical Specifications
OEM Part Numbers: 12138616153 12137594937 12137571643 12137594596
This vehicle uses a 'coil-on-plug' system with one ignition coil per cylinder, for a total of six 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.
- BMW 435i:
- 🛍️ Shop This Part
- Signs of a Failing Ignition Coil
- Choosing the Right Aftermarket Ignition Coil
- Tier 1: OEM & OEM-Equivalent Brands
- Pro Tip: Replace in Sets
- Tier 2: Performance Brands
- Tier 3: Standard Aftermarket Brands
- Known Issues & Bulletins
- Cost of Replacement
- Frequently Asked Questions
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