OE Quality
60-Day Returns

Denso 221-3503 Radiator
Overview of Denso Radiator for Mazda Miata
The Denso radiator part number 221-3503 is designed specifically for Mazda Miata models, providing reliable cooling performance. This radiator includes a transmission oil cooler, making it a comprehensive solution for engine and transmission temperature management.
- Core Height: 12.625 inches
- Core Width: 25.312 inches
- Core Thickness: 0.625 inches
- Inlet Diameter: 1.25 inches
- Outlet Diameter: 1.25 inches
- Includes Transmission Oil Cooler
Detailed Radiator Specifications
The Denso 221-3503 radiator features a core measuring 12.625 inches in height, 25.312 inches in width, and 0.625 inches in thickness. These dimensions ensure efficient heat dissipation for the Mazda Miata's engine. The radiator also includes a built-in transmission oil cooler with 1.25-inch inlet and outlet diameters, allowing it to manage both engine coolant and transmission fluid temperatures effectively. This dual functionality supports optimal vehicle performance and longevity.
Compatible Vehicles and Applications
This radiator is compatible with Mazda Miata models, engineered to meet the specific cooling requirements of this vehicle. It is suitable for addressing common cooling system issues such as:
- Overheating due to radiator core damage or clogging
- Transmission fluid overheating affecting shifting performance
- Leaks or cracks in the radiator core or tanks
- Reduced cooling efficiency from worn or corroded components
- Replacement of original equipment radiator for maintenance or repair
Installation Notes and Tips
When installing the Denso 221-3503 radiator on a Mazda Miata, ensure all hose connections match the 1.25-inch inlet and outlet diameters. Properly flush the cooling system before installation to prevent contamination. Verify that the transmission oil cooler lines are correctly connected to maintain transmission cooling. Follow manufacturer torque specifications for mounting hardware to avoid damage.
Quality Assurance and Warranty
Denso radiators are manufactured to meet OEM standards for fit, form, and function. The 221-3503 radiator undergoes rigorous quality control to ensure durability and performance. While specific warranty details are not provided here, Denso products typically come with a limited warranty covering defects in materials and workmanship. Consult the product documentation or supplier for exact warranty terms.
| Brand | Denso |
| Part Number | 221-3503 |
| Core Height | 12.6250 |
| Core Thickness | 0.6250 |
| Core Width | 25.3120 |
| Transmission Oil Cooler Included | Yes |
| Inlet Diameter | 1.2500 |
| Outlet Diameter | 1.2500 |
This part fits 7 vehicles. Search below:
| Year | Make | Model | Transmission | Position | Notes |
|---|---|---|---|---|---|
| 2005 | Mazda | Miata | Automatic | N/A | |
| 2004 | Mazda | Miata | Automatic | N/A | |
| 2003 | Mazda | Miata | Automatic | N/A | |
| 2002 | Mazda | Miata | Automatic | N/A | |
| 2001 | Mazda | Miata | Automatic | N/A | |
| 2000 | Mazda | Miata | Automatic | N/A | |
| 1999 | Mazda | Miata | Automatic | N/A |
* Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.
This part directly replaces or is cross-referenced with the following part numbers:
Cross-reference numbers are provided for identification purposes only. Always confirm fitment before ordering.