The milestone coincides with another landmark, with Holden celebrating 11 years since the first HFV6 was produced at the Victorian facility in 2003.
The millionth engine – a 3.6-litre unit, usually fitted to either a Commodore SV6 or Calais variant – will be retained at the HEO plant.
HEO plant manager Martin Merry praised the skill and hard work of the plant’s employees.
“Our mission is to build the ‘World Best Engines’ and we believe we do,” Merry said.
HEO produces more than 34 versions of the HFV6 for domestic and export markets. The 2.8-litre, 3.0-litre, and 3.6-litre petrol and LPG engines power a range of General Motors vehicles in Asia, Europe, and North and South America including the Buick GL8, Chevrolet Alpheon and Opel Antara.
Holden has been operating at the Fishermans Bend site since 1936 and built its first engine – a 2.15-litre six-cylinder unit for the 48-215 ‘FX’ – in 1948.
The plant will close at the end of 2017 alongside Holden’s vehicle manufacturing operations in Elizabeth, leading to the loss of 1300 Victorian jobs and 1600 in South Australia.