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Siam Toyota Manufacturing Co Ltd

Product / Service We Provide

Nature of Business

Manufacture of engine for motorcar and pick-up truck.

Engine Assembly:

Casting Part:
Cylinder Block Toyota - 2L, 5L-E
Isuzu - 4JA1, 4JB1, 4J
Nissan - TD 27
Propeller Shift - 5A, 4E

A Leader in Production
STM clearly understands that to produce the highest quality engines, we must have the finest production facilities. This is why both plants have been installed with the most advanced machinery. Furthermore, we are afforded the full cooperation of our parent companies in Thailand and Japan who assist us by providing the latest breakthroughs in technology and methods to keep our manufacturing and products at the industry forefront.

Layout of the factory is based on the idea of a "Smooth Flow" and production system is designed to maintain the most efficient movement of materials to the production and assembly processes. Attention is also paid to providing the most comfortable working environment so operators can work with least amount of strain.

Production Process
At all time, attention is still focused on producing the highest quality products efficiently. In our factory, the basis is TPS (to eliminate "muda") with the idea  of "High quality" is built-in and ensured in each process. In 1994, the company introduced "Total Quality Management" for further upgrading of all employees and development of even more effective management.

Quality For A Better World
The highest quality production will produce the highest quality products. By continually introducing the latest innovations in technology and methods, manufacturing and assembly can be constantly upgraded so that STM can produce still finer, top standard engines and at increased capacity to meet growing market demands.

Year Established


Paid Up Capital

  • $62,000,000 USD

No. Of Employees

  • 3914

Key Persons

President - Virayot Prutakorawong

Company Background

Siam Toyota Manufacturing Co., Ltd. or STM, was established with a registered capital of 150 million baht on 6 July 1987 to produce gasoline and diesel engines for installation in locally assembled Toyota Hilux pickups as well as for export.  A joint venture between The Siam Cement Public Company Limited, Toyota Motor Corporation of Japan and other shareholders, STM was granted Board of Investment promotional privileges in September of the same year.

STM's first plant in Latkrabang began operations to produce engines in 1989, and in 1994, opened the iron casting plant in Bangpakong.  The Latkrabang plant was located to Bangpakong in 1997.  Today, employees number approximately 700 are producing around 110,000 units annually with a sales revenue of 8,000 million baht.

  • 1987 July : Company registration
  • 1987 September : Granted promotional privileges by the Board of Investment.
  • 1989 July : Started manufacturing diesel & gasoline engines for domestic & export consumption.
  • 1989 September : Official opening ceremony
  • 1990 July : Started second localization plan (up to 30%)
  • 1990 August : Started casting project
  • 1990 September : Increased registered capital from 150 million to 250 million baht.
  • 1991 June : 100,000 units of engines produced
  • 1991 July : Started third localization plam (up to 40%)
  • 1991 September : Increased registered capital from 250 million to 350 million baht.
  • 1992 July : Started fourth localization plant (up to 50%)
  • 1992 October : Started construction of Bangpakong plant.
  • 1993 March : H.E. Deputy Prime Minister visited Latkrabang Plant.
  • 1993 April : 200,000 units of engines produced.
  • 1994 June : Started cylinder block production at Bangpakong Plant.
  • 1994 July : 300,000 units of engines produced. Localization achieved up to 60%
  • 1994 September : Started camshaft export to Japan
  • 1994 December : Increased registered capital from 350 million to 850 million baht.
  • 1996 November : Started the production of gasoline E/G for Soluna
  • 1997 February : Started the production of 1600cc. E/G for Toyota Corolla and 2000cc. for Corona.
  • 1997 August : Relocated Latkrabang Plant to Bangpakong
  • 1999 January : Achieved 3,000,000 man-hour of working without lost working day accident.
  • 1999 May : Started the production of 2000cc. E/G for Toyota Camry
  • 1999 December : Achieved 1,000,000 cylinder blocks production

Main Shareholders / Parent Company

  • Toyota Motor Corporation
  • Amata City Chonburi Industrial Estate, 700/109, 111, 113 Moo 1, Bankao Sub-District
    Phanthong District, Chon Buri, 20160, Thailand
  • +66 (0)38 213451
  • +66 (0)38 213447
  • Distributor Required
  • Partnership Required
  • Looking to Sell
  • Looking to Buy