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Author Topic: Laptop overheating or noisy fan - Cleaning the cooling system.  (Read 977 times)

IainB

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Thought this might be of general hep/use. Let me know where it may need correcting/improving please.

First off: Install Speedfan http://www.almico.com/speedfan.php.
Use it to study your laptop and make a note of the current typical CPU and GPU temps in normal operation and under different load types  - e.g. (say), when playing games, or browsing the web or building a spreadsheet.
This will provide you with a starting-point as a basis for comparison - a factual AS-IS picture.

Causes of overheating:
  • As a long-time laptop user, I have learned that the single most common cause of overheating and fan noise in my laptops tends to be that the heat exchanger becomes clogged. The heat exchanger looks like a small radiator matrix (grill), usually located on the left or right side of the laptop, but sometimes on the rear side.

  • A small fan sucks the unfiltered cold air (usually from the base) into the laptop, and pushes it as exhaust hot air through the matrix of the heat exchanger.

  • The heat exchanger gets heat transferred to it via thermal conduction along a solid copper bar that picks up the heat and carries it away from the CPU (and GPU if fitted). The bar is screwed/clamped to the CPU/GPU, with a heat-conducting thermal grease smeared between the faces of the components before they are assembled. The grease can break down over some years and its conductive efficiency reduced as a result, leading to overheating and automatic thermal cut-out.

  • Over time, the heat exchanger matrix tends to become blocked with the accumulated dust and fluff that unavoidably accumulates (sucked/blown in by the fan). In addition, the blades of the fan can become loaded with accumulations of particles of dust, such that the fan aerodynamics can change and its weight can be increased appreciably and thus its operational and aerodynamic efficiency is impaired. These things can lead to overheating, fast/noisy fans and automatic thermal cut-out.

To see what you may need to clean:
NB: If you don't like the idea of using a vacuum cleaner to suck back through the fan, then go to the thorough clean section, below.
  • Step 1: Have on standby:
     - a horsehair paintbrush.
     - a variable-speed vacuum cleaner.
     - a bright LED torch.
     - a few plastic bag ties (with the wire center).

  • Step 2: Turn the laptop off and remove the battery.

  • Step 3: Shine a torch into the fan's cold air-intake (assuming there is one). Observe whether the intake is blocked with fluff/dust and the condition of the fanblades - if the latter are black, then they are probably not too dirty, but if a grey colour then they are probably loaded with dust/dirt. Wipe/dust off the intake surface with the paintbrush. Don't clean it otherwise, just make a mental note of the visible status.

  • Step 4: Next, whilst In a darkened room, shine a torch into the fan intake whilst looking through the heat exchanger matrix on the side of the laptop. The light should be visible The matrix should appear to consist of clear, rectangular little tubes, but they will be unable to let light through to varying degrees if they are blocked at all. Make a mental note of the status.

  • Step 5: Press the round end of the vacuum cleaner pipe against/over the air intake vent, sealing the edges with your fingers so that most of the suck is through the fan intake. Then SUCK: Turn on the vacuum cleaner and hold it in that position for around 2-5 seconds (experiment). The airflow will be sucked backwards through the fan (which you will hear whizzing backwards) and the air intake, along with most of the crud blocking the heat exchanger matrix. After switching off the vacuum cleaner, on inspection, you may need to slowly ease out larger chunks of fluff with a fine screwdriver, from the air intake vent. Repeat the suck until the air intake seems clear.

    Then repeat Step 4. Check - If the matrix seems clear/unblocked and if the fanblades are relatively black and shiny and the air intake is clear, then you probably don't need to do anything further.
    If the fanblades seem clean enough (black and shiny), but the heat exchanger matrix still seems a bit blocked, then you can clear the matrix further by using one of those plastic bag ties with a wire centre. Poke it through each hole in the matrix from the outside, then, when you have done that  thoroughly to them all, reverse-suck as before to clean the dislodged crud out.
    Inspect per Step 4 again.

    Step 6: Restart the laptop and check performance compared with the  AS-IS Speedfan performance metrics. If there's no change, then you probably need to do a more thorough clean, as below.
___________________________

DIY steps to do a thorough clean: (i.e., laptop is still overheating, cutting out, or has a noisy fan.)
  • If possible, download a manufacturer's service manual for that laptop. Read up on removal of the necessary parts to get access to those I have mentioned.

  • Prepare a clean work surface with a white cotton or microfibre towel to cover it.

  • Have on standby:
        - a good strong magnet (to hold metal screws on disassembly).
        - a horsehair paintbrush.
        - isopropyl alcohol.
        - a variable-speed vacuum cleaner.
        - cotton ear-buds (to clean in confined spaces - also use with isopropyl alcohol).
        - toilet paper (for cleaning surfaces - also use with isopropyl alcohol).
        - a bright LED torch.
        - heat-conductive thermal grease (if required).

  • Disassemble the laptop CAREFULLY as necessary to get the access required to clean its innards. Place the screws on the magnet so as not to lose them. Keep the magnet in a small tray or bowl to catch any screws or metallic bits that may fall off or are non-magnetic. You may find some screw anchors have already broken (or break on reassembly - so take care!) due to over-tightening or (typically) the plastic having become brittle (their design being unfit for long life).

  • Clean dust/dirt off the motherboard and other parts as you proceed inwards, using the paintbrush and vacuum cleaner on low suction. Using CO2 pressure cans to blow the dust off is arguably a waste of time as it tends to redistribute a lot of the dust (along with your money).

  • Clean the heat exchanger in situ. You may need to use a small flat-bladed screwdriver to scrape off accumulated fluff/dust/dirt or corrosion. Use a torch shone through it to check whether all the holes in the heat exchanger are cleared and clean.
    Carefully remove and disassemble the delicate fan, and separate the fan blade unit. The fan operates upside down and when operational hangs in the air utilising a magnetic field as a bearing (frictionless bearing). In operation, the upside-down rotating fanblade unit over time can become gradually more weighed-down with accumulated deposits of airborne grease and dust onto the fanblades. It can cease to be in its optimum aerodynamic blade profile or position, so becomes less efficient and can become noisy. The noise may be due to friction between surfaces where there should be no contact (or friction) in the optimal case.

  • Carefully clean the fanblade and housing using the paintbrush/earbuds/isopropyl alcohol, as necessary. After cleaning the fan and its housing, clean the bearing "faces" and smear them lightly with a fine coat or drop of CRC - or similar lubricant that can be used with electronics. Don't drown it with CRC as the excess oil will be thrown out along the fanblades when in operation, attracting and adhering to dust particles that pass through.

  • Heat-conductive thermal grease: You probably only really need to tackle the task of cleaning off and replacing the heatsink thermal grease if the CPU/GPU has been overheating and shutting down the system. I read somewhere that the grease has a 10-year life expectancy. I have tended to replace it only when I have opened up a laptop for the usual full cleaning (as above) and as a just-in-case measure on older laptops. Speedfan metrics will generally be a good guide as to whether this overheating is a problem. Those greases seem quite expensive, but maybe you get what you pay for. I'm not sure.

  • Reassembly: This is the reverse of disassembly, so, if you don't have a service manual, then make notes as you disassemble the thing.
« Last Edit: December 21, 2019, 10:08 AM by IainB »

holt

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« Last Edit: December 14, 2019, 05:04 PM by holt »

Shades

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Re: Laptop overheating or noisy fan - Cleaning the cooling system.
« Reply #2 on: December 15, 2019, 12:14 AM »
Some additions:

  • Clean dust/dirt off the motherboard and other parts as you proceed inwards, using the paintbrush and vacuum cleaner on low suction. Using C02 pressure cans to blow the dust off is arguably a waste of time as it tends to redistribute a lot of the dust (along with your money).

Vacuum cleaners suck air and dust, that is true. However, this suction creates a vortex of air and is known to generate static electricity in the process. Compressed air doesn't generate static electricity. A damp cloth for collecting dust particles/fluff etc. placed in the direction of where you are to blow air is just as good. Better is to work in a well vented area or simply do the blowing of air outside.

Oh, to prevent damage to fans, blowing or sucking air can make the fan turn in RPMs it was never designed for. You wouldn't be the first to damage the fan more by cleaning it than the dust/cruft could ever do. So it is necessary to physically stop the fan (or fans) from rotating at all, when cleaning out dust. Slowly rotating the fan(s) when cleaning debris from fan blades is fine. If physical access to fan or fans is possible, use a finger or toothpick to stop the fan from rotating.

Light application of grinded (ground?) graphite (the dark stuff inside a standard pencil) on the rotating body of the fan(s) where friction is most likely to occur also makes the fan turn smoother. If done right. A smooth running fan draws much less power than one that has trouble rotating. You can quickly test the smoothness of rotation by yourself blowing gently into the fan and see how quickly the fan blades stop moving. Less power consumed usually results in cooler running computers.

Heck, graphite also works well when you have a (slightly) stuck key on your keyboard.

Canisters of air are a bit of a rip-off. Personally, I use an air compressor that is normally used for bicycle tires. And then only ultra short bursts. Doing that twice a year for almost 15 years and haven't destroyed a computer yet. But if that sounds daunting, you can buy hand devices that blow air in a similar way like compressed air canisters, except you don't need to constantly buy new canisters of air for it.

  • Heat-conductive thermal grease: You probably only really need to tackle the task of cleaning off and replacing the heat-sink thermal grease if the CPU/GPU has been overheating and shutting down the system. I read somewhere that the grease has a 10-year life expectancy. I have tended to replace it only when I have opened up a laptop for the usual full cleaning (as above) and as a just-in-case measure on older laptops. Speedfan metrics will generally be a good guide as to whether this overheating is a problem. Those greases seem quite expensive, but maybe you get what you pay for. I'm not sure.

Better replace the thermal conductive paste every 5 years. That is what I do and still have three 15 year old systems (Linux, GUI-less) in operation, each doing one task. My boss likes the adagio of 'if it ain't broken...'). While most systems use a paste (not grease, never ever grease!), there are also thermal pads that manufacturers use to transfer the heat from the CPU/GPU to their heat-sink, which are in turn cooled by the fan or fans inside your laptop. These pads last longer, but are less efficient than most paste is.

Paste comes in various degrees of heat conductivity. And that is usually the difference between cheap(er) and expensive paste. Visit overclock forums to get an idea of good paste brands. Paste works best when it is lightly applied to the top surface of the chip you are trying to cool. While the surface of a chip that needs cooling might feel like a butter smooth surface to the touch, it really isn't.

Ideally, you'll put just enough to fill the creases of that chip surface with the paste, so the surface of the chip and the heat-sink make 100% contact over the full contact surface. Put more paste, and you'll decrease the capacity of the heat-sink's capacity to collect the generated heat. Less is more, so make sure that you use 3 or 4 little drops of paste in strategic locations on the CPU to get that 100% coverage. Use less drops for smaller chips.

Never ever use both thermal pads and paste! Only thermal paste or only pads. Cannot stress that part enough.