Our History

Marlo Coil HistorySince 1925, our company has manufactured quality heat transfer, refrigeration, and air handling equipment for industrial, commercial, utility, and marine markets. Our custom engineered Marlo heat transfer solutions are used in a variety of configurations to cool, heat, and dehumidify air streams for process and building comfort.


  • Marlo Coil HistoryIn 1925 Caesar and Angelo Marlo formed Marlo Coil.
  • From 1941-1945, World War II need for naval capability presented Marlo Coil with the opportunity to supply coils for naval vessels around the world.
  • The end of the war created the need to develop more commercial ways to satisfy built up demand for products of all sorts. A superb piece of good fortune saw the post‑war electrification of the United States. Hundreds of small towns built private electric power generating stations using diesel engine driven generators.  The majority of these tiny plants were not on waterways and the diesel engine oil systems had to be site cooled.
  • Marlo Coil manufactured a die to flatten round tubes and create excellent heat transfer coils for oil cooling. Marlo Coil filled the need for so many multi-hundred horsepower oil coolers.
  • In 1967 the Marlo family sold Marlo coil to the H.K. Porter Holding Company.
  • In 1974, H.K. Porter Holding Company liquidated Marlo Coil.  However, when one has a long list of unshipped Navy orders, it is not possible to totally shut down production and other arrangements were made. David Ault financed the purchase from Porter—for the dies, files, etc., necessary to fill the Navy orders. A vacant section of the Ford plant in St. Louis was rented and the rebirth was effected under the name of Nuclear Cooling, Inc.,
  • In 1976 David Ault purchased the exclusive rights to the name Marlo Coil.
  • In 1980, new facilities for manufacturing were built in High Ridge, Missouri, totaling 210,000 sq. ft.  Centrally located in the U.S., this production facility is just 30 minutes from downtown St. Louis, Missouri.
  • In 1998, Marlo Coil was acquired by Engineered Support Systems, Inc.
  • In 2006, Marlo Coil was acquired by DRS Technologies in the merger with Engineered Support Systems, Inc. creating DRS Marlo Coil.
  • In 2008, Marlo Coil was acquired by Finmeccanica Company in its acquisition of DRS Technologies.
  • In 2017, DRS Technologies changed from “DRS Technologies a Finmeccanica Company” to “Leonardo DRS”.

Marlo Coil History