What type of spark plugs does the classic Focus use?
2 Answers
Classic Focus spark plug model is TR6F13. What are spark plugs composed of: Spark plugs mainly consist of terminal nut, insulator, terminal stud, center electrode, side electrode, and shell. What types of spark plugs are there: Main types of spark plugs include: standard spark plugs, projected insulator spark plugs, electrode spark plugs, seat spark plugs, pole spark plugs, and surface gap spark plugs. How spark plugs work: Under high voltage, the air between the center electrode and side electrode of a spark plug rapidly ionizes, forming positively charged ions and negatively charged free electrons. When the voltage between electrodes reaches a certain value, the number of ions and electrons in the gas increases like an avalanche, causing the air to lose its insulating properties and forming a discharge channel in the gap, resulting in a "breakdown" phenomenon. At this point, the gas forms a luminous body, known as a "spark." Along with thermal expansion, a "snapping" sound also occurs. The temperature of this electric spark can reach 2000-3000°C, which is sufficient to ignite the air-fuel mixture in the engine combustion chamber.
Last year I just replaced the spark plugs on my 2008 classic Focus. The 1.8L engine originally came with Champion RFC58ZY nickel alloy spark plugs, while the 2.0L version used ZFR6F-11. Actually, many veteran owners have switched to NGK BKR6EIX iridium plugs, which have the same heat range of 6 as the OEM ones. But be aware that spark plugs may vary across different production years and batches - I recommend checking the codes on the old plugs during removal for the most accurate match. OEM plugs typically last 20,000-30,000 km, while upgraded iridium ones can go up to 60,000 km, but you'll need to regularly check the electrode gap. If doing it yourself, you'll need a 16mm spark plug socket, and avoid over-tightening to prevent thread stripping.
