How do I read an NGK glow plug part number to choose the right one?

The **full code must be matched** — not just thread or length. For example, a Y-204T plug is different from a Y-204TS1: both fit the same size thread, but the suffix tells you the heating speed and temperature rating. Always use the complete NGK code from your manual, catalog, or our Fitment Check tool to get the correct plug.