Can you replace a PSU fan with a smaller one?

[Tenderness]

My PSU's fan makes a very distracting sound.
Other fans in the case aren't nearly as annoying.
I've tried oiling it up like the tutorials said, "remove sticker, put one drop of oil", nothing changed.
The fan is 140mm. But I have a spare fan that's 120mm, can I use it instead? Would it overheat the PSU?

 

[Harvey]

That's a bad idea for many reasons:

1. A 140 mm fan is around 0.8" bigger in diameter than a 120 mm fan. The mounting holes won't match up, and the smaller fan would probably fall through the opening.

2. For cooling, the main concern is air flow. Discounting factors like the efficiency of the fan blade design, a larger fan will move more air at the same RPM than a smaller fan. To move the same amount of air, a smaller fan would have to spin faster and, thus, probably make more noise.

If you want a quieter fan, get a 140 mm fan rated at the same voltage, with the same mounting dimensions, that is specified to move at least as much air as the one in your PSU with double ball bearings and a low specified noise level.

 

[Tenderness]

That's a bad idea for many reasons:

1. A 140 mm fan is around 0.8" bigger in diameter than a 120 mm fan. The mounting holes won't match up, and the smaller fan would probably fall through the opening.

2. For cooling, the main concern is air flow. Discounting factors like the efficiency of the fan blade design, a larger fan will move more air at the same RPM than a smaller fan. To move the same amount of air, a smaller fan would have to spin faster and, thus, probably make more noise.

If you want a quieter fan, get a 140 mm fan rated at the same voltage, with the same mounting dimensions, that is specified to move at least as much air as the one in your PSU with double ball bearings and a low specified noise level.

1. I can take care of that. Just screw one end in and superglue the other.

2. I'm not concerned about the smaller fan being noisier, I know it will be quieter because there's something inherently wrong with the 140mm fan that's making a weird noise. My concern is if the PSU can make the smaller fan spin faster or will treat it like a 140mm fan and cause overheating.

 

[Harvey]

Clearly, engineering is not your strong suit.

1. I can take care of that. Just screw one end in and superglue the other.

1. That's a really bad idea. There's a reason most fans have four mounting holes. You're going from four point to two point mounting, which will be more vulnerable to vibration, and even that is tenuous because, if the PSU or anything else in the case gets warm enough, your glue joint could break.

2. I'm not concerned about the smaller fan being noisier, I know it will be quieter because there's something inherently wrong with the 140mm fan that's making a weird noise. My concern is if the PSU can make the smaller fan spin faster or will treat it like a 140mm fan and cause overheating.

No, unless it's a variable speed fan on a variable controller, it won't spin at any rate other than what it's designed to do.

Newegg has 140 mm fans starting at $7 and ball bearing units starting at $12.

Why would you want to work so hard to save so little while doing an intrinsically poor job when all you need is an inexpensive plug and play part?

 

[Tenderness]

1. That's a really bad idea. There's a reason most fans have four mounting holes. You're going from four point to tow point mounting, which will be more vulnerable to vibration, and if the PSU or anything else in the case gets warm enough, your glue joint could crack.

If it will make a vibrating noise then I would remove it.

No, unless it's a variable speed fan on a variable controller, it won't spin at any rate other than what it's designed to do.

It's a variable fan.

I would also like a guide on how to properly disassemble, clean and oil a fan.
Maybe if I strip the fan naked I could find something causing the noise.

 

[Harvey]

The only tools you need are the correct phillips screwdrivers. You may need two sizes, a 1/4" blade and a relatively finer blade for some smaller screws. You may also need a soldering iron and the ability to use it.

1. Unplug the machine from the wall, and all cables from the PSU to the motherboard and other items.

2. Remove the PSU from the case.

3. Remove the screws (typically four) holding the cover. Put them someplace where you won't lose or spill them.

4. CAREFULLY pull off the cover, being careful not to pull too hard on the wire nest inside.

5. If the fan is plugged into the ciruit board, unplug it. If it's soldered, just be careful not to break the wires while moving things around.

6. Remove the fan from the PSU. Typically fans are held by four fat screws that cut their own threads into plastic.

If it's soldered into the circuit board, you may want to remove the circuit board to get to the solder side so you can unsolder the wires. The circuit board may be held down by smaller phillips screws. That's why you may need the smaller phillips screwdriver.

If it's plugged into the circuit board, just buy a fan with the same connections, or, if you can handle a soldering iron, you can cut the plug off the old fan with an inch or two of wire, and splice that onto bare wires from the new fan. Use heat shrinkable tubing to cover the splices.

Once you've installed the new fan, reverse the above steps. The most important thing is, BE CAREFUL! After that, it's all easy.