Dorman 902-5821 Automatic Transmission Oil Cooler Thermostat - To Radiator

Reliable Automatic Transmission Oil Cooler Thermostat for BMW Models

The Dorman 902-5821 automatic transmission oil cooler thermostat is designed to maintain optimal transmission fluid temperature for a range of BMW vehicles. Engineered with durable plastic and precise temperature control, this thermostat helps protect your transmission system from overheating and ensures efficient operation.

• Material: High-quality plastic construction for durability
• Port Quantity: Single port design with 1.24-inch outside diameter
• Color: Black finish for corrosion resistance
• Opening Temperature: Activates at 176 degrees Fahrenheit to regulate fluid flow
• Overall Length: Compact 2.75 inches for easy fitment
• Includes thermostat and thermostat housing for complete replacement

Product Details and Specifications

The Dorman 902-5821 thermostat is specifically engineered for automatic transmission oil cooling systems. Its plastic material offers resistance to heat and corrosion, while the single port with a 1.24-inch outside diameter ensures compatibility with the transmission cooler lines on select BMW models. The thermostat opens at 176 degrees Fahrenheit, allowing transmission fluid to circulate through the cooler only when necessary, preventing premature cooling and maintaining optimal operating temperature. The compact 2.75-inch length facilitates straightforward installation without requiring modifications.

Compatible BMW Models and Applications

This automatic transmission oil cooler thermostat is compatible with various BMW vehicles, including the 320i, 323Ci, 323i, 325Ci, 325i, 325xi, 328Ci, 328i, 330Ci, 330i, 330xi, X3, X5, and Z4 models. The Dorman 902-5821 part number ensures precise fitment for these vehicles, making it a suitable replacement for worn or faulty thermostats in the transmission cooling system.

Common Issues Addressed by This Thermostat

• Prevents transmission fluid from overheating during heavy use
• Reduces risk of transmission damage caused by improper fluid temperature
• Helps maintain smooth shifting and transmission performance
• Prevents premature wear of transmission components due to temperature fluctuations
• Eliminates transmission overheating warning lights related to cooling system faults

Installation Notes and Tips

Installation of the Dorman 902-5821 thermostat requires draining the transmission fluid and removing the existing thermostat housing. Ensure the vehicle is cool before beginning work to avoid burns. Verify the port size and orientation match the original part. Replace the thermostat and housing as a unit to ensure proper sealing and function. After installation, refill transmission fluid to the recommended level and check for leaks. It is advisable to consult the vehicle’s service manual for torque specifications and detailed procedures.

Quality Assurance and Warranty

Dorman parts are manufactured to meet or exceed OEM standards, providing reliable performance and durability. The 902-5821 automatic transmission oil cooler thermostat undergoes rigorous quality control to ensure consistent operation under demanding conditions. While specific warranty details may vary, Dorman typically offers limited warranties covering defects in material and workmanship. Refer to the product packaging or Dorman’s official documentation for exact warranty terms.