Introduction
Product Overview
The ARCTIC Liquid Freezer II 420 is an all-in-one (AIO) liquid CPU cooler designed for efficient heat dissipation from your processor. It features a PWM-controlled pump and three 140mm fans, providing quiet yet powerful cooling for a range of Intel and AMD sockets.

This image displays the complete ARCTIC Liquid Freezer II 420 unit, highlighting the large radiator with three pre-installed fans and the compact pump/cold plate unit connected by two braided tubes.
Safety Information
General Precautions
- Ensure your system is powered off and unplugged before installation or maintenance.
- Handle components with care to avoid damage.
- Keep out of reach of children.
- Do not attempt to open the pump or radiator as it contains coolant.
- Refer to your motherboard and CPU manuals for additional compatibility and safety guidelines.
Package Contents
Verify that all components are present before beginning installation:
- 1 x Liquid Freezer II 420 AIO Cooler (Radiator with 3x P14 PWM fans, pump/cold plate, and tubing pre-assembled)
- Mounting hardware for Intel sockets (1700, 1200, 115X, 2011-3, 2066)
- Mounting hardware for AMD sockets (AM5, AM4)
- 1 x ARCTIC MX-4 Thermal Paste (0.8g)

The product packaging box, confirming the inclusion of ARCTIC MX-4 thermal paste, which is essential for CPU installation.
Specifications
| Feature | Specification |
|---|---|
| Product Dimensions | 18.01"L x 2.66"W x 5.43"H |
| Brand | ARCTIC |
| Power Connector Type | 4-Pin |
| Voltage | 12 Volts |
| Wattage | 1.44 watts |
| Cooling Method | Water |
| Compatible Devices | Intel Socket: 1700, 1200, 115X, 2011-3*, 2066* *Square ILM; AMD Socket: AM5, AM4 |
| Noise Level | 0.3 Sones |
| Material | Aluminum, Copper, Rubber |
| Maximum Rotational Speed | 1700 RPM |
| Air Flow Capacity | 72.8 cfm |
| Item model number | ACFRE00092A |
| Item Weight | 4.37 pounds |
| Tube Length | 450 mm |
| Radiator Dimensions | 458 (L) x 138 (W) x 38 (H) mm |
| Pump (w/o tubes) Dimensions | 98 (L) x 78 (W) x 53 (H) mm |

This diagram provides precise measurements for the radiator, fans, and pump/cold plate, crucial for checking case compatibility before installation.
Setup and Installation
Pre-Installation Checklist
- Ensure your PC case has adequate clearance for the 420mm radiator (458mm L x 138mm W x 38mm H).
- Identify your CPU socket type (Intel LGA1700, 1200, 115X, 2011-3, 2066 or AMD AM5, AM4).
- Gather necessary tools: screwdriver, thermal paste (included).
Installation Steps
Follow these general steps for installation. Refer to the official user manual (PDF link provided in product data) for detailed, socket-specific instructions.
- Prepare the Motherboard: Install the correct backplate and standoffs for your CPU socket.
- Apply Thermal Paste: Apply a small amount of the included ARCTIC MX-4 thermal paste to the center of your CPU's integrated heat spreader (IHS).
- Mount the Pump/Cold Plate: Carefully place the pump/cold plate assembly onto the CPU, aligning it with the standoffs. Secure it with the provided screws.
- Mount the Radiator: Install the radiator and fans into your PC case. The Liquid Freezer II 420 is designed for front or top mounting depending on case compatibility. Ensure proper airflow direction.
- Connect Cables: Connect the single 4-pin PWM cable from the pump to your motherboard's CPU_FAN or PUMP_FAN header. The fans are integrated into the sleeved tubing, simplifying cable management.
Operating Instructions
PWM Control
The ARCTIC Liquid Freezer II 420 utilizes Pulse Width Modulation (PWM) for precise control over both the pump and fan speeds. This allows your motherboard to dynamically adjust cooling performance based on CPU temperature, optimizing for both cooling efficiency and noise levels.
VRM Fan Operation
An additional 40mm VRM fan is integrated into the pump housing. This fan provides supplementary cooling to the Voltage Regulator Modules (VRMs) on your motherboard, which can significantly reduce VRM temperatures, especially under heavy CPU loads. This fan also operates via PWM control.
Maintenance
Dust Cleaning
Regularly inspect the radiator fins and fans for dust accumulation. Use compressed air or a soft brush to gently remove dust from the radiator and fan blades. Ensure the system is powered off and unplugged before cleaning.
Coolant System
The Liquid Freezer II is a closed-loop AIO system and does not require coolant refills or maintenance. Do not attempt to disassemble the unit or open the tubing, as this will void the warranty and may cause damage.
Troubleshooting
High CPU Temperatures
- Check Thermal Paste: Ensure thermal paste was applied correctly and evenly.
- Verify Mounting Pressure: Confirm the pump/cold plate is securely mounted to the CPU with adequate pressure.
- Fan/Pump Connection: Ensure the 4-pin PWM cable is properly connected to the motherboard's CPU_FAN or PUMP_FAN header. Check BIOS settings to ensure fan control is enabled.
- Airflow: Verify that the radiator fans are oriented correctly for optimal airflow (intake or exhaust, depending on your case configuration).
Unusual Noises (Gurgling, Whining)
- Air Bubbles: Initial gurgling sounds are normal as air bubbles settle in the loop. This should subside within a few hours of operation.
- Pump Orientation: Ensure the pump is not the highest point in the loop to prevent air from accumulating in the pump.
- Fan Noise: Check if any cables are obstructing fan blades.
Warranty and Support
Warranty Information
The ARCTIC Liquid Freezer II 420 comes with a 6-year warranty. Please retain your proof of purchase for warranty claims.
Customer Support
For technical assistance, warranty claims, or further inquiries, please visit the official ARCTIC support website or contact their customer service. A digital version of this manual and additional resources may be available on their website.
For a comprehensive guide, you can download the official user manual: ARCTIC Liquid Freezer II User Manual (PDF)





