Where do you find the spark plug number?
The spark plug part number is usually visible on the plug itself or listed in your vehicle’s documentation. This article explains where to look and how to read it to ensure you buy the correct replacement.
In practice, the exact plug type your engine requires is specified by the manufacturer and may be printed on the plug, on packaging, or in manuals and labels. Knowing where to look saves time and helps ensure you buy the correct replacement with the right heat range and gap.
On the spark plug itself
Here are the common markings you’ll see directly on the spark plug itself and what they mean.
- Printed or stamped on the ceramic insulator near the terminal end, often as a line of letters and numbers with the plug model (e.g., NGK BKR6E-11).
- Stamped or etched on the metal shell or hex portion; some brands place part numbers here.
- Other codes may denote heat range, gap, or construction; these are also used when matching to a specific engine.
If markings are faded or unreadable, photograph the plug or compare with a current replacement from the same engine model, and verify with the manufacturer’s specifications.
In vehicle documentation and labeling
If the plug itself isn’t readable or you want to confirm the exact part number, check your vehicle’s documentation and labeling.
- Owner’s manual: Maintenance or Specifications sections list the recommended spark plug type, including the part number or cross-reference to brands.
- Service manual or dealer documentation: OEM part numbers are specified for your exact engine code and model year.
- Under-hood stickers or engine bay labels: Some manufacturers place a label near the engine that lists the recommended plug type for your motor.
- VIN-based lookup on manufacturer or parts retailer sites: Entering your VIN can yield the exact spark plug number for your vehicle.
Use these sources to confirm the correct plug for your engine if the plug itself is unclear or you’re replacing worn parts for a specific model year.
How to ensure you get the right plug
To make sure you purchase the correct spark plug, follow these checks.
- Match the heat range and thread size to your engine specifications.
- Verify the correct reach and gasket type for your cylinder head.
- Cross-reference with your owner's manual or official parts listing, especially if you’re changing brands.
When in doubt, consult the dealership or a qualified technician to verify the exact part number for your vehicle.
Summary
Locating the spark plug number is usually straightforward: check the plug itself for stamped or printed markings, consult the vehicle’s owner or service manual, review any under-hood labels, or use a VIN-based lookup on a manufacturer or parts retailer site. Always verify heat range, thread size, and gap to ensure a proper fit and optimal engine performance.
What's the code for spark plugs?
Spark plug codes are a series of letters and numbers that specify a spark plug's characteristics, such as its thread size, reach, and heat range. Each manufacturer uses its own system, so a code like 'BPR6ES-11' from NGK is broken down into components like the thread size (B), resistor (R), heat range (6), special feature (E), and projected insulator (S). The final number, if present, indicates the recommended gap in tenths of a millimeter.
This video explains what spark plug numbers mean, including the codes for thread diameter, heat range, and material: 58sOne-Up Moto GarageYouTube · Sep 15, 2025
Example breakdown of an NGK code like BPR6ES-11
- B: Thread size (e.g., 14mm)
- P: Projected insulator
- R: Built-in resistor to reduce radio frequency interference
- 6: Heat range (lower number = hotter plug, higher number = colder plug)
- E: Thread reach
- S: Special design
- -11: Gap (1.1mm)
Other codes to look for
- Thread diameter and reach: These are often the first letters and determine if the plug will physically fit in your engine's cylinder head.
- Electrode material: Letters like 'IX' indicate an iridium center electrode, while 'GP' can mean platinum.
- Heat range: This is a number that indicates how hot or cold the tip of the spark plug runs. It's determined by how quickly the plug can dissipate heat from the combustion chamber.
- Gasket type: Codes like 'ES' or 'G' can indicate a stainless steel gasket.
- Special features: Codes can also represent special features such as a taper cut (Z), a projected insulator (B), or a specific application like LPG (T).
How to find the right spark plug
- Check your vehicle's manual: The owner's manual will list the exact specifications for the correct spark plug for your engine.
- Look at the old spark plug: You can pull out one of the old spark plugs and look for a brand name and number printed on the porcelain insulator. You can use this information for a cross-reference or to find a replacement.
- Use an online tool or ask an associate: Online tools or an associate at an auto parts store can help you cross-reference your vehicle's information to find the correct part number.
What does the number on a spark plug mean?
heat range
The heat range of a spark plug is the range in which the plug works well thermally. The heat rating of each NGK spark plug is indicated by a number; lower numbers indicate a hotter type, higher numbers indicate a colder type.
How do I tell which spark plugs I need?
To find the recommended spark plugs for your vehicle or machine, check your owner's manual. If your owner's manual specifies iridium spark plugs, don't downgrade to platinum spark plugs or copper spark plugs; if you downgrade, you run the risk of poor engine performance.
Which spark plug is number 1?
The "number 1" spark plug is in the number one cylinder, which is the cylinder at the front of the engine, closest to the accessory drive or timing cover. You can confirm its location by checking your vehicle's owner manual, which often has a diagram of the engine's firing order, or by locating the cylinder and the corresponding spark plug wire terminal on the distributor cap, which will point to the correct spark plug when the rotor is positioned at top dead center (TDC).
This video explains how to identify the cylinders in a V6 engine: 23sWirelesSHackYouTube · Jun 22, 2024
How to find cylinder #1
You can watch this video to learn how to identify cylinder #1 in a V8 engine: 26sWirelesSHackYouTube · Sep 30, 2024
- For inline engines: Cylinder #1 is the one at the very front of the engine, closest to the pulleys and belts.
- For V-type engines: Cylinder #1 is the forward-most cylinder in either the driver's side or passenger's side bank. Check your manual to see which bank is designated as bank #1.
- For distributor-equipped engines:
- Rotate the engine to top dead center (TDC) for the compression stroke in cylinder #1. You can do this by hand, feeling for pressure as you turn the crankshaft pulley.
- Remove the distributor cap and look at where the rotor is pointing. The terminal it's pointing to is the location for the #1 spark plug wire.
