GOLF,,, MK2,,,1.3,,,1.6,,,1.8 GTi (NOT 16v),,,,1984 > 1992. GOLF,,, MK3,,,1.6i,,,1.8i,,,,1992 >. They have a waterproof seal around the spark plug and are resistant to oil, water and under-bonnet corrosive materials.Ignition leads connect the distributor to the spark plugs and therefore form an important part of the overall car engine ignition system.