There are many OEMs for Sonata thermostats, the more well-known ones are as follows:

Our company has professional product research and development ability, and experienced production team. We develop more than 50 models per year. All products adopt high quality raw materials. With advanced ultrasonic and vibration friction welding technology, professional production and testing equipments, we are going to provide reliable, durable, efficient, safe products to customers.
Ningbo Xite Auto parts Co., LTD. established in 2015, specializing in the production of thermostat assembly,water temperature sensor , heater valve and other auto spare parts.
- Changzhou Jiatong Auto Parts Co., Ltd.: Changzhou Jiatong Auto Parts Co., Ltd. is a first-tier supplier of Hyundai Motor, providing thermostats, water pumps, intake and exhaust pipes and other components for Hyundai Motor.
- Shanghai Sonata Auto Parts Co., Ltd.: Shanghai Sonata Auto Parts Co., Ltd. is a first-tier supplier of Shanghai General Motors, providing thermostats, water pumps, intake and exhaust pipes and other components for Shanghai General Motors.
- Dalian Huayang Auto Parts Co., Ltd.: Dalian Huayang Auto Parts Co., Ltd. is a professional manufacturer of auto parts, providing thermostats, water pumps, intake and exhaust for FAW-Volkswagen, Shanghai Volkswagen, Shanghai GM and other automakers Piping and other parts.
- Yantai Moon Auto Parts Co., Ltd.: Yantai Moon Auto Parts Co., Ltd. is a professional manufacturer of auto parts, providing thermostats, water pumps, intake and exhaust pipes for Dongfeng Motor, FAW-Volkswagen, Shanghai Volkswagen and other automakers and other parts.
- Changzhou Toshiba Automotive Air Conditioning Co., Ltd.: Changzhou Toshiba Automotive Air Conditioning Co., Ltd. is a wholly-owned subsidiary of Toshiba in China, providing Toshiba with thermostats, water pumps, intake and exhaust pipes and other components.
The above are some well-known Sonata thermostat foundries, in no particular order. It should be noted that when choosing a foundry, in addition to the strength and reputation of the foundry, factors such as product quality, delivery time, and price must also be considered.