In short, the 2008 BMW 335i uses iridium-tipped spark plugs—six in total, one per cylinder. Replacements are typically OEM-equivalent iridium plugs from NGK or Bosch, with exact part numbers varying by market and VIN.
The 2008 335i is equipped with the N54 twin-turbo inline-6 engine. Spark plugs sit beneath the coil packs on the cylinder head, and replacing them is a six-plug job to maintain balanced ignition across all cylinders. Common guidance suggests a replacement interval around 60,000 miles under normal driving, though more aggressive use can shorten that interval. Always verify the correct plug gap and torque to BMW specifications for your specific vehicle.
Engine context and plug type
The N54 engine family, used in the 2007–2010 335i, relies on iridium-tipped plugs designed for longevity in a turbocharged setup. There are six plugs, one for each cylinder, and replacing all six at once helps preserve ignition timing and performance. The typical target gap for these plugs is about 0.028 inches (0.7 mm), but you should confirm the exact gap for your chosen part number in the service literature or parts catalog.
Replacement options
Here are the plug options commonly used by owners and technicians when servicing the N54-equipped 2008 335i. Using OEM-equivalent iridium plugs from reputable brands is standard practice.
- NGK Iridium IX spark plugs (iridium-tipped, suitable for the N54 when matched to the correct heat range).
- Bosch Iridium Twin Spark plugs (iridium-tipped, designed for modern BMW engines).
- BMW/Mini Genuine Spark Plugs (OEM-equivalent iridium plugs matching the N54 requirements).
Note: Exact part numbers vary by market and vehicle VIN. Always confirm the correct plug specification with an authorized dealer or trusted parts retailer before purchase.
Maintenance notes
Before replacing spark plugs on the 2008 335i, consider these steps to ensure proper installation and engine health.
- Verify the engine code (N54) and disconnect the battery or follow appropriate safety protocol.
- Remove coil packs one at a time and replace each six plugs in sequence to preserve proper alignment.
- Set the spark plug gap to the recommended specification (approximately 0.028 inches / 0.7 mm for many iridium plugs in this engine).
- Torque the new plugs to the BMW specification (commonly around 20 Nm, but verify for your exact plug and model year).
- Reinstall coil packs, clear any codes if necessary, and test for smooth idle and proper ignition.
Concluding note: Replacing all six plugs at once is standard practice for the N54 to maintain balanced performance across all cylinders, especially in a turbocharged six.
Safety and procurement tips
When shopping for plugs, prioritize OEM-equivalent iridium plugs from reputable brands and avoid mixing plug types across cylinders. If you’re unsure about the correct part number for your market or VIN, consult your dealer or a trusted automotive parts retailer. Use proper tools, work in a clean environment, and follow torque specifications closely to prevent thread damage in the aluminum cylinder head.
Summary
The 2008 BMW 335i’s spark plugs are iridium-tipped, six-pack units designed for the N54 turbocharged inline-6 engine. Replacements are typically OEM-equivalent iridium plugs from NGK or Bosch, with the exact part number dependent on market and VIN. Target a gap near 0.028 inches and torque around BMW’s specified value, replacing all six plugs together and following the manufacturer’s maintenance intervals for optimal performance.