A Guide to Spark Plug Replacement for the 2013-2022 BMW 740i
Keep your BMW 740i running smoothly by understanding when and how to replace your spark plugs.
- Identify your engine: 2013-2015 models have the N55, while 2016-2022 models have the B58. They use different plugs.
- Choose the right brand: For stock performance, Bosch (N55) and NGK (B58) are OEM-quality choices that offer great value.
- Shorten replacement intervals for tuned cars: If your 740i is tuned, change plugs every 15,000-25,000 miles to avoid misfires.
- Consider replacing ignition coils at the same time, especially on higher-mileage vehicles, to save on future labor costs.
Understanding Your 740i's Engine
Before buying spark plugs, it's crucial to know which engine your 740i has. The 2013-2022 model years span two different engines with different spark plug requirements:
- 2013-2015 BMW 740i (F01/F02): Equipped with the N55 inline-6 engine.
- 2016-2022 BMW 740i (G11/G12): Equipped with the B58 inline-6 engine.
Always verify your vehicle's model year and engine type before purchasing parts.
Symptoms of Failing Spark Plugs
Worn spark plugs can cause a range of noticeable issues. Your car might feel 'off' or exhibit more specific symptoms. 🎬 Watch: A visual guide to common bad spark plug symptoms. Common signs include:
- Engine Misfires: The engine may stumble or hesitate, especially under acceleration. This can feel like a shudder or a loss of power and may trigger the Check Engine Light.
- Rough Idle: Your car may vibrate or shake more than usual when stopped.
- Reduced Fuel Economy: Worn plugs can cause inefficient fuel combustion, making you fill up more often.
- Poor Acceleration: The car may feel sluggish or slow to respond when you press the gas pedal.
- Difficulty Starting: A weak spark can make it harder for the engine to turn over.
Choosing the Right Aftermarket Spark Plugs
When it comes to spark plugs for your BMW, you have a few quality choices. The term "aftermarket" can sometimes mean a drop in quality, but for this part, some aftermarket brands are the original equipment (OEM) suppliers, offering the same part without the BMW logo and price tag.
Brand Comparison: Bosch vs. NGK vs. Champion
Bosch: Bosch is a primary OEM supplier for many BMWs, including the N55 engine. Their plugs are known for reliability and longevity, making them a safe, high-quality choice for a stock 740i. For the N55, the Bosch ZR5TPP33 is a go-to option for stock power levels.
NGK: NGK is another OEM supplier for BMW, particularly for the B58 engine. They are highly regarded by enthusiasts and mechanics for both stock and high-performance applications. For tuned engines, NGK offers 'colder' heat range plugs that are better at handling the increased temperatures of a modified engine. For the B58, the NGK SILZKGR8B8S (94201) is a very popular and trusted option.
Champion: Champion plugs were used as original equipment in some B58 engines around 2018. However, they have a mixed reputation in the BMW community. Some owners have reported premature failures, leading many to recommend sticking with Bosch or NGK.
| Brand Tier | Typical Price Range | Notes |
|---|---|---|
| New OEM (Dealer) | $25 - $45+ | Highest cost. Often a rebranded Bosch or NGK plug. |
| New Aftermarket (Premium) | $15 - $30 | Includes top-tier NGK Iridium and Bosch Double Platinum plugs. Excellent performance and value. |
| New Aftermarket (Standard) | $10 - $18 | Good quality options from OEM suppliers like Bosch that meet factory specs. |
Known Issues, Recalls, and TSBs
There are no specific recalls for spark plugs on the 2013-2022 BMW 740i. However, a few related items are worth noting:
- Installation Errors: A very common cause of misfires after a plug change is cracking the plug's porcelain insulator during installation. This is often invisible to the naked eye. Using the correct tools and torque is critical.
- Loose Plugs: There have been reports of spark plugs being loose from the factory or a previous service, leading to fuel leaks and other issues. Plugs should always be tightened to the correct torque specification (23nm for the B58). 🎬 See this step-by-step spark plug replacement for G12 B58 engines.
- Starter Motor Recall: Some 2020-2022 740Li models were part of a recall for an overheating starter motor, which is unrelated to spark plug function but is an important safety check for affected vehicles.
Frequently Asked Questions (FAQ)
How often should I change the spark plugs on my 740i?
BMW's recommended interval is typically every 60,000 miles for a stock vehicle. However, if your car is tuned or you drive aggressively, you should shorten this interval significantly, to as little as 15,000-25,000 miles.
Is this a DIY job?
For an experienced home mechanic, yes. The process is straightforward, but accessing the rearmost plugs requires removing several plastic covers and components. A special thin-walled 14mm 12-point spark plug socket is required for many modern BMWs, including the N55. If you are not comfortable with this, it's best to leave it to a professional.
Should I replace my ignition coils with my spark plugs?
It's a good idea, especially if your car is near or over 80,000 miles. The ignition coils sit directly on top of the spark plugs and must be removed to access them. Replacing them at the same time is cost-effective preventative maintenance that can save you from doing the same labor twice if a coil fails later.
Do I need to gap my new spark plugs?
Most high-quality plugs from NGK and Bosch come pre-gapped for the stock application. It is always a good practice to verify the gap with a feeler gauge 🎬 Watch: How to properly gap and change your N55 plugs. before installation. Dropping a plug can easily change the gap. For tuned applications, your tuner may recommend a specific, smaller gap.
Frequently Asked Questions (FAQ)
How often should I change the spark plugs on my 740i?
BMW's recommended interval is typically every 60,000 miles for a stock vehicle. However, if your car is tuned or you drive aggressively, you should shorten this interval significantly, to as little as 15,000-25,000 miles.
Is this a DIY job?
For an experienced home mechanic, yes. The process is straightforward, but accessing the rearmost plugs requires removing several plastic covers and components. A special thin-walled 14mm 12-point spark plug socket is required for many modern BMWs, including the N55. If you are not comfortable with this, it's best to leave it to a professional.
Should I replace my ignition coils with my spark plugs?
It's a good idea, especially if your car is near or over 80,000 miles. The ignition coils sit directly on top of the spark plugs and must be removed to access them. Replacing them at the same time is cost-effective preventative maintenance that can save you from doing the same labor twice if a coil fails later.
Do I need to gap my new spark plugs?
Most high-quality plugs from NGK and Bosch come pre-gapped for the stock application. It is always a good practice to verify the gap with a feeler gauge 🎬 Watch: How to properly gap and change your N55 plugs. before installation. Dropping a plug can easily change the gap. For tuned applications, your tuner may recommend a specific, smaller gap.
Helpful Videos
Technical Specifications
OEM Part Numbers: 12120037582 12120040581 12122455258 12125A4EF60
For the N55 engine (2013-2015), the OEM plug is typically a Bosch Double Platinum plug. For the B58 engine (2016-2022), the OEM plug is often an NGK Laser Iridium or Champion Iridium plug. A 14mm thin-wall, 12-point spark plug socket is required for N55 service.
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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 740i: