Calorific value: The gap at the spark plugs must be adjusted to the temperature of the combustion chamber generated in the engine. This quality is called the heat of combustion. Its index indicates what temperature the spark plug can withstand, i.e. can dissipate heat without becoming too hot itself. If the spark plug removes more heat than necessary, then it does not reach its cleansing temperature and the spark plug electrodes become coated with soot.
Electrodes: Renault 19 uses only spark plugs with an end electrode.
Thread: on Renault 19 spark plugs, the length of the threaded part is 19 mm; thread diameter is 14 mm.
Wrench size: hex spark plug wrench on engine type «WITH» and on the engine type «F» up to 81 kW has a width of 20.8 mm (= 13/15"), on a 16-valve engine it is 16 mm in size (= 5/8"). This motor requires a long socket wrench.
O-Ring: All engines require spark plugs with a flat sealing surface. They are equipped with a non-removable sealing ring and do not require additional sealing.