Spark plug · NGK
Equivalents for the NGK spark plug 6421
NGK 6421 is an automotive spark plug. Compare its 33 equivalents and find the cheapest compatible plug: NGK, Bosch, Champion, Denso and more.
Buy this spark plug NGK 6421 — best retailers
Partner links: a purchase made through these links may earn us a commission, at no extra cost to you.
What can replace a NGK 6421 spark plug?
The NGK 6421 is interchangeable with: NGK BM7F, Bosch HS 5 E, Champion DJ6J, Champion DJ7J, Denso T22M-U, Denso WA22M. These spark plugs share the same mounting (thread, seat) and heat range.
Cross-references and specifications are provided for guidance only. The wrench size can vary by brand, and some data is inferred from the plug code or an equivalent reference. Always check the vehicle manufacturer's recommendation before buying and fitting.