BMW has claimed that driving their vehicles results in “Sheer Driving Pleasure” for over fifty years. In most instances, BMW models have lived up to this tagline, and in part, the engines are one of the primary reasons they have been so successful.
Spark plugs are one of those engine parts that you know need to be replaced from time to time and BMW spark plugs certainly are not the cheapest out there. So how frequently do you need to replace BMW spark plugs?
BMWs require spark plugs to be changed between 20,000 – 80,000 miles. BMWs fitted with copper spark plugs have a replacement interval of 20,000 miles, those equipped with Platinum spark plugs should be replaced every 80,000 miles, and the rest fall between these.
Spark plugs are those unseen devices that work very hard in extreme heat and are expected to continue delivering the goods thousands of miles without a misstep. You need to change these low-cost items, designed for durability and performance needs at BMW’s recommended intervals.
Different BMW Models Have Varying Sparkplug Intervals
Because different BMWs use different sparkplugs and operate at various maximum revolutions and different heat ranges, BMW recommends different spark plug change intervals for varying engine models.
- BMWs fitted with the four-cylinder N20 manufactured after 2010 require a spark plug change every 60,000 miles.
- BMWs powered by the straight-six N55 engines require a spark plug change every 60,000 miles.
- BMWs with the N54 straight-six petrol engines should have spark plugs replaced every 37,000 miles.
- Cars fitted with the N63 twin-turbocharged V8 petrol engine must also have the spark plugs changed every 37,000 miles
- All other BMW models fitted with V8 or V10 engines should have spark plugs changed every 37000 miles.
- Apart from the above stipulation, cars manufactured between the years 1999 to 2022 should have spark plugs replaced at 80,000 miles if you are using Platinum or Iridium-tipped spark plugs.
- Older BMWs will typically have copper/nickel alloy spark plugs, which will need to be changed between 20,000 – 25,000 miles.
What Does A Sparkplug Do?
Spark plugs form the third leg of the internal combustion mix. Internal combustion engines are powered by a mini “explosion,” which occurs at the millisecond the piston reaches the top of the combustion cycle. The resulting gasses expand, force the piston down, and leave the piston chamber via the exhaust port.
All fire (combustion) requires three ingredients to start and continue. Remove one of the elements, and there will be no combustion.
- Fuel
- Air
- Spark
The fuel/air is mixed by the BMW’s fuel injection system and delivered to each piston at just the right moment. Once the mixture is provided, the spark plug receives a burst of 20,000-25,000 volts of current from the coil attached to the spark plug.
When the coil generates a spark, combustion occurs, and the piston is forced down and turns the crankshaft, which delivers energy to the gearbox and drives the wheels.
For a four-cylinder BMW engine, operating at a red line of 7,000 revs per minute, each plug needs to generate 25 high-quality sparks every second.
What Are The Different Types Of Sparkplugs?
Four different sparkplugs are used in BMW engines, each having unique properties.
Copper/ Nickel Alloy Spark Plugs
For better heat resistance, copper spark plugs comprise a solid copper core center electrode covered with nickel alloy.
Spark plugs made from copper with nickel alloy electrodes run at relatively cooler temperatures and, due to the excellent conductivity properties of copper, deliver higher power in performance driving situations.
Copper/nickel Alloy spark plugs are often used as original equipment in turbocharged engines and engines with high compression ratios.
BMWs with a distributor-based ignition system manufactured before 1990 often use copper/nickel alloy spark plugs.
Both materials (nickel and copper) have relatively low melting points, 1,983F and 2,642F, respectively, which result in higher wear rates. The wear on the electrodes opens the electrode gap, resulting in a misfire and lower gas mileage. It can also cause damage to the coil and ignition wires.
These spark plugs are not expected to last more than 20,000 miles.
That being said, copper spark plugs typically will not be your best replacement option unless you are running a track car. In that case, you won’t want to touch anything but copper spark plugs.
Platinum Spark Plugs
BWM engines manufactured between the 1990s and 2009 came out of the factory with Platinum spark plugs.
The plugs consisted of a platinum core and had electrodes made from Platinum. Platinum has a higher melting point, 3,218º F, making them more durable than copper/nickel spark plugs.
The platinum spark plugs installed on BMWs have an additional platinum disc welded to the tip of the side electrode and are called double platinum spark plugs.
The additional platinum disc produces a better spark and results in increased efficiency.
Because Platinum has a higher melting point, it can run hotter, and the recommended distance between changes was increased to 80,000 miles.
Iridium Spark Plugs
Iridium spark plugs are used in select BMWs.
Spark plugs manufactured from iridium have an even higher tolerance to heat, with the melting point increased to 4,442º F.
Iridium spark plugs last approximately 25% longer than platinum spark plugs.
Iridium plugs have smaller electrode tips which increase the spark efficiency and improve fuel economy and engine performance.
Pulstar Spark Plugs
Pulstar spark plugs are the highest-performing units.
From the outside, they look like regular spark plugs. However, they are equipped with an internal capacitor developed by the US Department of Energy laboratory, which stores energy to create a high-intensity electrical pulse when required.
The spark looks like an electrical pulse with a wider boundary and saturates the fuel with combustion-enhancing plasma, ensuring a rapid burn.
The Pulstar spark plugs deliver a more robust and consistent energy pulse, ensuring the BMW engine:
- Starts quickly
- Idles smoothly
- Generates more torque
- Causes an improvement in fuel economy
- As more fuel is burnt with each spark, less gas is emitted out of the exhaust port, which produces fewer emissions
BMW Spark Plug Comparison Table
| Spark Plug | Average Cost | Average Lifespan |
|---|---|---|
| Copper/Nickel Alloy | $3-$5 per plug | 20,000 - 25,000 miles |
| Platinum | $8-$15 per plug | 80,000 miles |
| Iridium | $15-$25 per plug | 80,000 - 100,000 miles |
| Pulstar | $20-$25 per plug | 50,000 miles |
Where Brand Of Spark Plug Is Best For BMW?
There are so many different brands out there for spark plugs; NGK, Bosch, Champion, AC Delco, etc.
Personally, my go-to favorite spark plugs are the NGK Laser Platinums. NGK is an outstanding brand, and besides the fact that the box is really nice, they make one hell of a spark plug.
What Can Shorten A Spark Plugs Lifespan?
Keep in mind that the recommended intervals for BMW spark plug replacement are based on that your vehicle runs in reasonably good condition and you have kept to the maintenance schedule on other key components.
Failure to properly maintain your engine will end up shortening the lifespan of your spark plugs.
Here are a couple of issues that can cause spark plugs to fail prematurely:
- Driving with bad spark plug tube seals. There are rubber seals that go between the valve cover and the spark plug tube. Overtime the rubber seals become brittle and crack. When this occurs, oil can leak down into the spark plug tubes and this will foul the spark plugs.
- Overheating engine. Overheating a BMW engine is a big NO NO. Driving an overheated engine can cause all sorts of problems for your BMW and premature death of your spark plugs certainly is not the worst thing that can happen.
- Incorrectly gapped spark plugs. Thankfully, the vast majority of spark plugs nowadays come pre-gapped to your vehicles specifications. However, if for some reason the spark plugs are not gapped correctly they will be placed under additional stress and will fail prematurely.
How Difficult Is It To Replace BMW Spark Plugs?
On MOST BMWs, spark plug replacement is fairly simple and easy to do. I have owned an E36 (replacement video here), E46, E90, and a Z4, and spark plug replacement was quite simple on every one of these vehicles (about an hour).
Unfortunately, some BMWs turn a simple spark plug replacement into a grueling repair. Most notably, I owned a BMW X5 and replacing the spark plugs on this vehicle was by far the worst spark plug job I have ever done. You can read all about my problematic experience owning an X5 here.
Here is a great video on replacing spark plugs for a modern 3 Series BMW:
The Signs That A Spark Plug Need Replacing
Some common warning signs that a spark plug in a BMW is not working optimally:
- The BMW engine may not start as readily as normal
- Because the spark plug is not firing correctly, more fuel will need to be delivered to the engine to produce sufficient power and thus your fuel economy will decrease
- A really worn spark plug may not fire with each electrical pulse resulting in the engine misfiring
- A defective ignition coil may damage the spark plug resulting in the above symptoms
Always use the spark plugs that the vehicle’s manual recommends. Most BMWs can take spark plugs made of any one of these materials listed above, but the size and gap will be engine specific. It is important to research the optimal spark plug for your vehicle and for what kind of use you intend to get out of your vehicle.
If you are unsure which spark plug types will provide optimal efficiency for your BMW, check with a BMW dealership or an independent BMW technician for advice.
Conclusion
BMW engines are very technologically advanced units. To ensure peak efficiency and power, all the consumables (spark plugs, coils, oil, etc.) you use in the engine must be correctly specified to provide optimal performance for your car.
Driving a BMW is rewarding, and the sound produced by the legendary six- or eight-cylinder engines when are they are delivering high power is very expressive. Using the correct spark plugs and changing them as required will ensure that the BMW continues to captivate your emotions.
References
https://www.bmw.com/en/automotive-life/the-history-of-the-bmw-slogan.html
https://en.wikipedia.org/wiki/BMW_N20
https://www.yourmechanic.com/article/symptoms-of-bad-or-failing-spark-plugs