Laptop Refurbishment Part 1 – Thermals

Laptop Refurbishment Part 1 – Thermals

I refurbished a DELL XPS 15 L502X for my parents.

The laptop was running very hot and slow.

I decided that in order to refurbish the laptop I would:

  1. Clean the fan and heat sink
  2. Replace the stock thermal paste
  3. Replace the Hard Drive with an SSD
  4. Replace and increase the RAM
  5. Do a clean install of Windows 10 (This was Windows 10 upgraded from Windows 7)

This post will cover the first two points and a follow up post will cover the rest.

The CPU was running at 65 Degrees Celsius at idle (very hot for idle, ideal would probably be around 40 Degrees Celsius).

A good free tool for getting information about a PC such as thermals, RAM, models numbers, etc is Speccy.

I decided to tackle this problem by first cleaning the fan intakes, exhausts, heat sink channels and the fan, then I would replace the stock thermal paste. After some research I discovered that Dell’s stock thermal paste is optimised for longevity not thermal conductivity.

I bought Cooler Master thermal paste from a local supplier. I don’t think it matters what brand of paste you buy as long as it has high thermal conductance (>4W/m-K), and very low/no electrical conductance. I also bought Isopropyl Alcohol (IPA) and a small plastic syringe from a local chemist for cleaning off the old thermal paste. The syringe is optional but makes it easier to apply the alcohol.

Before I start to repair/work on any electronics I always lookup the device on

They have step by step repair/disassembly guides on a huge range of electronics.

Unfortunately they have no fan replacement guide but the screen replacement guide will get me far enough that I can figure out the rest.

I also found a YouTube video about how to replace the fan (, but I find it easier to do disassembly/reassembly with written instructions.

iFixit also make excellent repair tools, I would strongly recommend their Pro Tech Toolkit and Magnetic Project Mat.

I disassembled the laptop down to the heat sink and fan (in the silver back panel), this was a fairly difficult disassembly process.

The project mat is great for organising screws and making disassembly notes and reminders.

I blew out the fan and heat sink air channels using an air compressor, they were very dirty and air flow was definitely restricted.

The CPU and Graphics Card are located under these heat sinks, we need to remove these to replace the thermal paste.

The old thermal paste can be seen on the heat sinks, we will need to clean this off using the alcohol.

Using the syringe place some of the alcohol on the old thermal paste and leave it for about a minute to soften the old thermal paste.

Using a clean rag wipe off the thermal paste.

Do the same to the GPU and the CPU. Be care not to damage anything when cleaning them.

Apply the thermal paste to the CPU and GPU using the tube as the applicator. I used the line method to get good coverage across the surface it is not necessary to spread it out as the pressure of the heat sink should spread it evenly. I applied more than needed as I wanted to ensure good contact between the two surfaces, but as it it is electrically non-conductive it doesn’t matter if there is a small bit too much paste as it will just squeeze out and should not cause any problems.

Next re-screw the heat sinks back onto the motherboard, make sure they are tight to ensure good contact but don’t over-tighten them as this may damage the motherboard.

Reassemble and test the laptop.

I saw the temperature of the CPU drop by about 5 Degrees Celsius after I did these changes, I am hoping a Windows reinstall will help it to drop further.

The fan on this laptop also had a problem where it was constantly ramping up and down. After some research I found that there were settings that you could change to the cooling policy in the power settings that would fix this problem and it did. If you also have this problem then the steps to fix this problem are in this forum thread

In next weeks post (here) I will go through picking an SSD and RAM and replacing them and doing a clean install of Windows.


As always if you have any questions please don’t hesitate to ask,


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