Computer Services

Tel 650.548.1010
Burlingame, CA USA


Case Fan Installation

Revised on

While upgrading a friend's PC the other day I soon discovered (after the PC was running for a while) that the top/rear of the case was getting kind of hot. It wasn't hot, but warm on the top. This particular case didn't have good ventilation so I thought I'd install a fan in that hot spot.

How about a 80mm / 3 inch fan right on the top of the computer case directly above where the CPU is. Maybe just a little off center so not to be too close to the power supply.

Tools Needed

  • Drill. I have a Dewalt DW926 Cordless but any good drill will do. (fig. 2)
  • Metal Hole Saw 3 inch (or 80mm if you can find it). (fig. 3)
  • (Maybe a adapter to accommodate the small drill chuck) (fig. 4)


  • 80mm Fan. There are two types. The smaller newer 3pin (fig 5a) and the 4 conductor type (fig. 5b).
  • Grill Guard
  • 4 wood screws


Get Ready

The first time I ever attempted to drill a hole on a computer case it totally screwed it up. Have you ever used one of those floor strippers that would jump away if you didn't know what you were doing? Well, if you don't have the right azimuth when you start drilling your hole on the case it will jump all over the place and you'll scratch the top of your case all up. Not something to be proud of, I don't need to tell you...

A Good Opportunity

I'm sure that if your computer has been sitting on the floor like mine, its got a good amount of dust and spider webs inside and all around. Grab a good can of air or run it down to the Gas Station down the street to blow out the dust inside the case. Make sure to get all around the fans, inside the power supply and where the expansion cards are inserted. You can also blow out the CD-ROM thou make sure to keep it away a fair distance. If you don't the blast of air out of these air hoses could damage something inside the sensitive device.

Once you have 'er all cleaned out, you'll need to completely disassemble the computer... Yes, I know you'll hate this, but it's also another great opportunity to inventory all your parts, write don't model #'s, serial #'s and the like. Make sure to take note where each card was removed so this doesn't effect the OS discovery when you boot it up. In other words, if your modem was in slot 3, put it back in slot 3.

Drilling it

Position the case on a firm flat surface, preferably on the floor and straddle the case with both feet. (fig. 5)

Ready your drill with the 3 inch/80mm hole saw installed and start slowly... let the center drill bit (the thing the hole saw mounts to) turn into the case a few dozen revolutions at slow speed then when you think the drill bit has got a good bite into the metal, LET HER RIP! Continue drilling at the highest speed the drill will let you until you're through. Be very mindful to keep your drill level and your approach or the hole saw will start jumping around and you'll scratch the metal surrounding your hole.

Mounting the fan and grill guard

Using the grill guard, get a pen and line up the grill guard so it lines up the way you like it and place a mark using your Sharpie marker so you can drill a hole for the case fan screws.

Position the fan, grab your Phillips screwdriver and mount the grill to the case and fan.

Once you have 'er installed, grab your compressed air can or make another run to the gas station to blow out any little metal fragments. I would waste a whole can or air and get into every little crack, fold and crevice to blow out all those metal fragments.

Take note here kids, if one of these little tiny metal fragments falls onto your motherboard, it could short out something and you'll be most unhappy. Make sure to do this!

Reassemble your computer and stay cool!


- Michael










[ Click on any image to enlarge ]

Fig. X

Fig. X

Fig. X

Fig. X
Hold 'er steady...

Fig. X
Hole's Done!

Fig. X
Grill Guard

Fig. X
Case Fan Screws

Fig. X
Installed Fan Power Supply Removed

Fig. X
Installed Fan

Fig. X
Installed Fan

Fig. X
Installed Fan





Register for our FREE monthly drawing of computer stuff!