Volvo Cars Heritage has for a long time noticed how people often refer to the Volvo 1800 models using the wrong designations. This is not just done by people in general but also by owners of these cars who have difficulties in sorting out the right designation for their car. You find it to be very common especially in sales ads and in stories in the press.
In fact, it is not very complicated. This is what the cars should be called:
P1800 - cars produced from the start in 1961 to February1963
P1800S - cars produced from February 1963 until July 1963
1800S - cars produced from July 1963 until November 1969
1800E - cars (coupes) produced from November 1969 until June 1972
1800ES - cars (sportswagons) produced from 1971 until June 1973