How to Replace an AIO Cooler Pump

Signs your AIO pump needs replacement

An all-in-one (AIO) cooler uses a pump to circulate liquid between a cold plate on the processor and a radiator. When the pump starts to fail, the first sign is often a change in sound. A pump that is working properly makes a faint, steady hum. If you hear a gurgling, clicking, or grinding noise, the pump may be struggling. Another sign is a sudden rise in processor temperature during light work or at idle, which can cause the system to slow down or shut off to protect the hardware. Some motherboards also show a warning on the screen or light up a diagnostic LED when the pump header is not spinning.

If you suspect the pump is failing, check the pump speed in the system monitoring software that came with the motherboard or from the cooler maker. The speed is shown in revolutions per minute (RPM). If the reading is zero or much lower than the rated speed, the pump is not working as intended. You can also listen near the pump block while the system is on. If there is no sound at all, the pump may be completely stopped. These checks help you decide whether to replace the cooler or look for another cause, such as a loose cable or a fan that is not spinning. For more on monitoring temperatures, see how to monitor gaming PC temperatures.

Replacing the pump means replacing the entire AIO cooler, because the pump, cold plate, tubes, and radiator are sealed as one unit. You cannot swap just the pump. This article explains the process in general terms. For specific steps, refer to the manual that came with your cooler or the maker's website. The process is similar across most AIO models, but the mounting brackets and screw positions can differ.

What you need before you start

Before you begin, gather a few items. You will need a Phillips-head screwdriver, a clean cloth or paper towel, and a tube of thermal paste. Some coolers come with thermal paste pre-applied on the cold plate, but if you are reusing a cooler or the paste is not included, you will need to apply it yourself. You may also need a small brush or can of compressed air to remove dust from the case and the radiator fins.

Make sure you have a clear, flat work surface with enough room to lay the case down. Unplug the power cord from the wall and press the power button to drain any remaining charge from the capacitors. This is a safety step and also prevents the system from turning on while you work. You do not need to remove the processor from the motherboard, but you will need to access the area around the processor socket. In most cases, this means removing the side panel of the case. If the case has a glass side panel, set it aside on a soft surface.

It is also a good idea to have the manual for your new cooler on hand. The manual will show the correct mounting bracket for your processor socket, the order of the screws, and the recommended fan and pump header connections. If you do not have the manual, you can download it from the maker's website. Knowing the exact steps before you start will save time and reduce the risk of installing something incorrectly. If you need a new cooler, see our guide to 360mm AIO coolers.

Removing the old AIO cooler

Start by unplugging the fan and pump cables from the motherboard. The pump cable is usually a three-pin or four-pin connector labeled CPU_FAN or AIO_PUMP. The radiator fans are typically connected to headers labeled CPU_FAN_1, CPU_FAN_2, or SYS_FAN. Take a photo or note which header each cable was connected to, so you can connect the new cooler the same way.

Next, remove the radiator from the case. The radiator is usually mounted on the top or front of the case, held in place by screws that go through the case frame into the radiator. Remove these screws and gently lift the radiator out. Be careful with the tubes that connect the radiator to the pump block; they are not meant to be bent sharply. Set the radiator aside on a flat surface.

Now, remove the pump block from the processor. The pump block is the part that sits on the processor and contains the pump. It is held in place by a mounting bracket that screws into the motherboard. The bracket design varies by cooler model. Some use a single crossbar with four screws, while others use a ring that twists to lock. Loosen the screws in a diagonal pattern, a little at a time, to avoid putting uneven pressure on the processor. Once the screws are loose, lift the pump block straight up. If it feels stuck, twist it gently to break the seal of the thermal paste. Do not pry it with a screwdriver, as that can damage the processor or the motherboard.

After the pump block is off, clean the top of the processor with a cloth and a small amount of isopropyl alcohol if you have it. Wipe away the old thermal paste until the surface is clean and dry. Do the same for the cold plate of the new cooler if it has any residue. If the new cooler has pre-applied thermal paste, do not wipe it off. For more details on applying thermal paste, see how to apply thermal paste.

Installing the new AIO cooler

Before mounting the new cooler, check the mounting bracket that came with it. The bracket must match your processor socket. Most modern AIO coolers support both Intel and AMD sockets, but the bracket pieces are different. Follow the manual to attach the correct bracket to the motherboard. Some brackets screw into the backplate, while others clip onto the socket. Make sure the bracket is secure and aligned with the four mounting holes around the processor.

If the new cooler does not have pre-applied thermal paste, apply a small amount, about the size of a grain of rice, to the center of the processor. Do not spread it; the pressure of the pump block will spread it evenly when you tighten the screws. Place the pump block over the processor, aligning the screws with the bracket holes. Lower it gently so the cold plate touches the paste. Tighten the screws in a diagonal pattern, a little at a time, until they are snug. Do not overtighten; the screws should be firm but not forced.

Mount the radiator in the same position where the old one was, or in a position that fits your case. The radiator has screws that go through the case frame. Make sure the fans are attached to the radiator and that the fan cables are long enough to reach the motherboard headers. Connect the fan cables to the same headers you noted earlier. Connect the pump cable to the CPU_FAN or AIO_PUMP header. Some coolers have a separate cable for the pump and a splitter for the fans; connect them all. For help with fan curves, see how to set fan curves.

Before closing the case, double-check that all cables are connected and that nothing is pinched between the radiator and the case. Plug in the power cord and turn on the system. Enter the BIOS or UEFI setup by pressing the key shown on the screen during startup, often Delete or F2. Look for the hardware monitor or fan control section to see the pump speed. It should show a value above zero. If the pump speed is zero, the pump is not getting power or the header is not set to the right mode. Some motherboards require you to set the header to 'full speed' or 'PWM' mode in the BIOS for the pump to run correctly.

After confirming the pump is running, let the system sit at the desktop for a few minutes. Check the processor temperature in the monitoring software. It should be similar to or lower than the temperature with the old cooler. If the temperature is very high, the pump may not be seated properly, or the thermal paste may not be applied correctly. In that case, shut down, remove the cooler, and repeat the installation steps.

Choosing a replacement AIO cooler

When choosing a new AIO cooler, the main specification to look at is the radiator size. AIO coolers come in sizes such as 120mm, 240mm, 280mm, and 360mm, referring to the length of the radiator. A larger radiator has more surface area for the liquid to cool, which can help keep the processor cooler under heavy load. However, the radiator must fit inside your case. Check the case specifications for the maximum radiator size it supports, and check the clearance for the radiator thickness and fan height.

Another specification is the pump design. Some coolers use a pump that is integrated into the radiator, while others have the pump in the cold plate. Both designs work, but the mounting process can differ. The pump speed is often listed in the specifications, but a higher number does not always mean better performance. The important thing is that the pump is reliable and that the cooler is compatible with your processor socket.

If you are not comfortable replacing the cooler yourself, or if you want to avoid the risk of damaging the processor, consider a prebuilt gaming PC that comes with a reliable cooling solution. Many prebuilt systems include an AIO cooler that is already installed and configured. This can be a simpler path if you are not confident in your ability to install a cooler correctly. You can also choose a prebuilt with a high-quality air cooler, which has no pump to fail and is easier to maintain. See our guide to air CPU coolers for more information.

For those who want to keep the current system and replace the cooler, the process is straightforward if you follow the steps carefully. The key is to take your time, use the correct mounting bracket, and verify that the pump is running before you close the case. If you run into trouble, the manual and the maker's support pages are the best resources.

What to pick for your play

The right cooling solution depends on your processor and how you use the PC. For a gaming PC with a mid-range processor, a 240mm AIO cooler is often enough. For a high-end processor that generates more heat, a 360mm AIO cooler may be a better fit, especially if you play for long sessions or run demanding tasks like streaming while gaming. The radiator size also affects where you can mount it in the case, so check the case layout before buying.

If you are building a new system or upgrading a prebuilt, consider the cooling solution that comes with the PC. Some prebuilt gaming PCs include a 240mm or 360mm AIO cooler, while others use a tower air cooler. Both can work well, but an AIO cooler can be quieter under load because the fans are on the radiator, which is often mounted at the top or front of the case. An air cooler is simpler and has fewer parts that can fail, but it may be taller and can interfere with memory clearance.

For a gaming PC that will be used for competitive play at a high refresh rate, the processor does not need to be overclocked, so a mid-range cooler is sufficient. For a PC used for streaming or content creation, the processor may run at higher load for longer periods, so a larger radiator can help maintain consistent performance. The choice is about balancing the cooler's capacity with the case size and the processor's power draw.

What to pick for your play

Questions

How do I know if my AIO pump is failing?

Listen for unusual noises like gurgling or grinding, check the pump speed in monitoring software, and watch for higher processor temperatures at idle or light load. If the pump speed reads zero, the pump is likely not running. For more on monitoring, see how to monitor gaming PC temperatures.

Can I replace just the pump on an AIO cooler?

No, the pump is part of the sealed unit that includes the cold plate, tubes, and radiator. You must replace the entire AIO cooler.

Do I need to reapply thermal paste when installing a new AIO cooler?

Yes, if the new cooler does not have pre-applied thermal paste. Apply a small amount to the center of the processor before mounting the pump block. See how to apply thermal paste for guidance.

What should I do if the pump speed shows zero after installation?

Check that the pump cable is connected to the correct header and that the header is set to full speed or PWM mode in the BIOS. Also, verify that the cable is not damaged. For help with fan curves, see how to set fan curves.

Is it safe to use a prebuilt gaming PC instead of replacing the cooler myself?

Yes, a prebuilt gaming PC comes with a cooling solution already installed and configured. This avoids the risk of installing a cooler incorrectly and is a good option if you are not comfortable with the process.