Denso 221-3503 Radiator

Denso Radiator for Mazda Miata

Denso 221-3503 is a direct-fit radiator for the 1999-2005 Mazda Miata. Built to OE-style specifications, it supports consistent engine cooling with the fitment and dimensions needed for a proper replacement.

• Fits 1999-2005 Mazda Miata
• Core height: 12.6250 in.
• Core width: 25.3120 in.
• Core thickness: 0.6250 in.
• Inlet diameter: 1.2500 in.
• Outlet diameter: 1.2500 in.
• Transmission oil cooler included

OE-Style Cooling Performance

Denso 221-3503 is engineered around OE radiator requirements, including tank design, fin pitch, core dimensions, and material selection. That attention to configuration helps maintain proper coolant flow and heat transfer in the Mazda Miata, while the integrated transmission oil cooler supports vehicles equipped for that setup. Denso’s OE supply experience is reflected in the radiator’s fitment-focused construction and durability testing.

This part cross-references Spectra Premium CU2268 for the same application.

Common Reasons to Replace

• Coolant leaks from an aging or damaged radiator
• Overheating during stop-and-go driving or warm weather
• Restricted cooling performance from clogged internal passages
• Cracked tanks or weakened seams on the original unit
• Transmission cooling concerns on equipped Mazda Miata models

Installation Notes

Verify core dimensions, inlet and outlet size, and transmission cooler connections before installation. Flush the cooling system, inspect hoses and clamps, and confirm proper coolant fill and bleed procedures after replacement. For a 1999-2005 Mazda Miata radiator replacement, matching the OE-style layout helps ensure correct fitment and function.

Quality Assurance

Denso radiators are built to meet OE manufacturer standards and are subjected to durability and function testing before release. Part number 221-3503 is designed for reliable cooling performance under demanding operating conditions.