Denso 221-3506 Radiator

Denso Radiator for Mazda Protege

The Denso 221-3506 radiator is a direct-fit cooling system replacement for 2001-2003 Mazda Protege models. Built to OE-level specifications, it uses the correct core dimensions, inlet and outlet sizing, and an integrated transmission oil cooler to support stable engine temperature and transmission fluid management.

Key Features

• Fits 2001-2003 Mazda Protege
• Part number 221-3506
• Core height: 12.8120 in.
• Core width: 27.1870 in.
• Core thickness: 1.0000 in.
• Inlet diameter: 1.1250 in.
• Outlet diameter: 1.1250 in.
• Transmission oil cooler included

Detailed Description

Denso radiators are engineered using OE supplier experience and manufacturing standards that focus on fitment, cooling efficiency, and durability. The 221-3506 radiator is configured to match the original application for the Mazda Protege, with tank design, fin pitch, core size, and materials selected to meet strict OE requirements. For drivers searching for a Mazda Protege radiator replacement, this unit provides the dimensions and cooling features needed for proper engine operation.

This part cross-references Spectra Premium CU2303 for the same application.

Common Problems This Part Can Address

• Engine overheating from a leaking or restricted radiator
• Coolant loss caused by cracked tanks or damaged core passages
• Poor heat transfer from a clogged or corroded radiator
• Transmission fluid temperature concerns when the factory cooler is part of the system
• Fitment issues from using an incorrect Mazda Protege radiator size

Installation Notes and Tips

Verify inlet and outlet hose diameter before installation and confirm the radiator matches the vehicle’s original cooling layout. Inspect hoses, clamps, and coolant condition during replacement, and flush the system if contamination or corrosion is present. Because this radiator includes a transmission oil cooler, check all cooler line connections carefully during installation.

Quality Assurance

Denso radiators undergo durability and function testing to verify performance under demanding operating conditions. The brand’s OE manufacturing background supports consistent fitment and cooling performance for 2001-2003 Mazda Protege applications.