Denso 221-3701 Radiator

Denso 221-3701 Radiator for Hyundai Sonata and Kia Optima

Denso 221-3701 is a radiator built for direct-fit cooling system service on select Hyundai Sonata and Kia Optima applications. It uses OE-style dimensions and materials to support consistent engine temperature control, with an integrated transmission oil cooler for vehicles equipped with automatic transmission cooling through the radiator.

Key Features

• Core height: 15.7500 in.
• Core width: 27.8750 in.
• Core thickness: 0.6250 in.
• Inlet diameter: 1.3750 in.
• Outlet diameter: 1.3750 in.
• Transmission oil cooler included
• Built to OE configuration standards for fitment and cooling performance

Detailed Description

The Denso 221-3701 radiator is engineered around OE supplier experience, with radiator configuration, tank design, fin pitch, core dimensions, and materials selected to match manufacturer requirements. For 1999-2005 Hyundai Sonata and 2001-2006 Kia Optima models, this radiator supports proper heat transfer and stable cooling system operation. If you are replacing a leaking, clogged, or damaged radiator on a Hyundai Sonata or Kia Optima, Denso 221-3701 provides a direct replacement path with the correct inlet and outlet sizing and an integrated transmission cooler.

This part cross-references Spectra Premium CU2339 and CSF 2928 for the same application.

Vehicle Fitment

• Fits 2001-2006 Kia Optima, N/A
• Fits 1999-2005 Hyundai Sonata, N/A

What It Helps Solve

• Engine overheating caused by a restricted or failing radiator
• Coolant leaks from cracked tanks or damaged core sections
• Poor heat rejection from worn internal passages or fin damage
• Automatic transmission cooling issues when the radiator cooler circuit is compromised
• Fitment problems from using the wrong core size or hose connection dimensions

Installation Notes and Tips

Verify hose connection size, core dimensions, and transmission cooler line routing before installation. Flush the cooling system, inspect hoses and clamps, and confirm the radiator cap and coolant condition are in serviceable shape. After installation, refill with the correct coolant mixture and bleed air from the system according to the vehicle service procedure.

Quality Assurance

Denso radiators are built to OE standards and undergo durability and function testing before release. That process helps ensure dependable cooling performance and proper fitment for Hyundai Sonata and Kia Optima applications.