just serviced my daughters citroen c1,1.0 petrol and the spark plugs i removed are DENSO K20HR-U11 & the ones supplied are DENSO K16HR-U11 ! whats the difference ? genuine citroen parts and both the plugs look identical . thanks
K = Thread diameter (19.0mm / 16mm socket)
20 = heat range (16 presumably cooler)?
H = Plug reach (19.0mm thread + 8.5mm electrode)
R = Resistor built in
U = "U" groove in the earth electrode
11 = Gap (11=1.1mm).
