Background
My laptop has been running hot for the last few months which is not a good thing given it can damage the CPU, GPU, or motherboard but, I had a more annoying side effect, the fan was constantly running at high speed or kicking on/off all day long. I’ve known several people who have the HP nw8440 or slight derivatives of the 8440 and they have always had heat dissipation problems requiring the fan to always spin up. Mine lasted almost four years before the fan constantly ran so I figured it was time to dig into the issue.
I really had no idea what was causing the issue, I figured it could be dirt or the fan going bad so the only option was to tear it apart. Finding the manual and taking the laptop apart was definitely the most difficult part, cleaning and reassembly is extremely easy.
One note before you start or definitely before you take the GPU/CPU heat sinks off of the GPU/CPU you must have (or get) some thermal compound, see below for details.
| Thermal Compound |
|---|
| Thermal compound is a special grease that goes between the GPU and the GPU heat sink (or CPU and CPU heat sink). Thermal compound provides a channel for heat to dissipate off of the GPU/CPU and onto the heat sink which allows the GPU/CPU to cool properly. A tube of thermal compound can be bought online for less than $5 or you can get it from bestbuy for around $10. I got a 17oz tube which will probably cover 40-50 computers (needless to say, get the smallest tube you can as you don't need much) |
Details
After a bit of research, I found the manual for the 8440 on HP’s website (you will probably want the Service and Maintenance Guide) and promptly found the section(s) regarding how to take it apart. At first it seemed a daunting task unless you know a GPU heat sink from a CPU heat sink but a little common sense prevailed (CPU has a big CPU fan on it, GPU typically does not).
Disassemble
I took the keyboard off (2 screws on back and slide the four keyboard clips down), removed the CPU heat sink and fan, and pulled out the GPU heat sink and found my issue. Aside from the fact that the CPU heat sink and fan were a bit dirty, the GPU heat sink was completely caked with dust/grit. The GPU heat sink on the 8440 is on the far left side of the laptop and curls
around from the GPU (lower left of the laptop, near/under the [fn] key on the keyboard) to the vent on the left hand side of the laptop. You could not tell from the outside that the GPU heat sink was blocked but by pulling out the CPU heat sink you could see the issue right away.
Cleaning
The GPU heat sink is a solid piece of copper/brass so cleaning is easy. Simply run it under water, blow out the excess water/dirt, and dry it off. Cleaning the CPU heat sink/fan
is not quite as easy as it has a bit of electrical components attached so simply wipe off/blow as much dust/dirt off that you can.
Reassemble
Putting the GPU/CPU parts back in is a simple task of reversing what you did to take it all apart but there is one key step not to forget which is to wipe off the old thermal compound and apply new (see Thermal Compound above for info). Apply a small amount of compound, spread it to a thin layer that covers the CPU/GPU area which directly contacts the heat sink.
After you have cleaned the old thermal compound and put new on, put the GPU heat sink back in, then the CPU heat sink, followed by the keyboard and you are all set!
Final Result
The entire process took me an hour (minus going to bestbuy). It was several days before my fan kicked on at all, when it did it only kicked in the lower fan and it was due to watching The Office on hulu. I’ve used the laptop a lot since cleaning it and I’d say 80% of the time or more neither the low or high fan kicks on - success!
