The company was started in 1903 as Lee Stroyer, but two years later, following the departure of Stroyer, it was relocated to Paynes Lane, Coventry, and renamed to Coventry-Simplex. Throughout the 1920s and 1930s they supplied engines to many companies manufacturing light-cars. Going into the war, Coventry Climax used their marine diesel experience to further develop and build the Armstrong Whitworth supercharged H30 multifuel engine for military use. This has been fitted as an auxiliary engine in the British Chieftain and Challenger battle tanks and Rapier anti aircraft missile systems. In the late 1940s, the company shifted away from automobile engines and into other markets, including marine diesels, fire pumps, and forklift trucks.The company was purchased by Jaguar Cars in 1963, which itself merged with the British Motor Corporation (BMC) in 1966 to form British Motor Holdings (BMH). . In 1977 Coventry Climax acquired the Warrington forklift truck business of Rubery Owen Conveyancer, renaming it to Climax Conveyancer. In 1986 Coventry Climax went into receivership and was acquired by Cronin Tubular. In 1990, a further change of ownership came with the engine business being sold to Horstman Defence Systems of Bath, Somerset, thus breaking the link with Coventry. Kalmar Industries acquired the forklift truck interests of Coventry Climax in 1985. The company traded as "Kalmar Climax" for a few years, but is now trading as Kalmar Industries Ltd.