FAQ
TL;DR: "60 % of small-fan failures are lubrication-related" [Machinery Lubrication, 2020]. "Oil only, unless the fan is on bearings" [Elektroda, oldking, post #645811] Clean, then add one drop of ISO VG 32–46 synthetic or machine oil; avoid greases that clog pores. Why it matters: Correct lube cuts fan noise and heat risk for CPUs, GPUs, PSUs.
Quick Facts
• Sleeve-bearing pore size: 20–80 µm, so only thin oils penetrate [Wikipedia “Sintered bronze”, 2023].
• Recommended oil viscosity: ISO VG 32–46 for 2000–4000 RPM fans [SKF Lubricant Chart, 2022].
• Quality ball-bearing fans last ≈70 000 h at 40 °C [Sunon MF80251V2 datasheet, 2024].
• Replacement 80 mm fan costs €4–10 [Amazon price-scan, 2024].
What’s the best lubricant for a noisy sleeve-bearing PC fan?
Use a light machine or synthetic oil (ISO VG 32–46). It flows into the porous bronze bushing without clogging and stays in place by capillary action [Elektroda, oldking, post #645811] Avoid thick greases; they block the pores and the fan seizes quickly [Elektroda, oldking, post #645811]
Can I spray WD-40 or similar products on the fan?
Avoid solvent-rich sprays like WD-40; they rinse out existing oil and evaporate, leaving sticky residue that speeds wear [Elektroda, Ptych, post #647498]
Is edible cooking oil safe for temporary fan lubrication?
No. Vegetable oils polymerise when exposed to air, harden, and can lock the shaft within weeks [Elektroda, 0__0, post #646818]
How do I relubricate a sleeve-bearing fan in three quick steps?
- Peel back the hub sticker and pop the rubber plug. 2. Flush old residue with isopropyl alcohol and let it dry. 3. Add one drop (≈0.03 ml) of ISO VG 32 oil, reseal, and spin the blade by hand.
When is it smarter to replace the fan instead of lubricating?
If the shaft has notable radial play or the fan still growls after oiling, the bushing is worn; lubrication won’t restore alignment. Replace it to avoid thermal shutdowns [Elektroda, Ptych, post #647498]
Why does graphite grease fail inside computer fans?
Graphite grease is too thick and blocks the micro-channels that store oil in sintered bushings, causing rapid seizure [Elektroda, Artur79, post #646370]
Which automotive oils work in a pinch?
Light gearbox oils (SAE 75W-80) meet the needed viscosity and cling well at 40–60 °C, but ensure they lack tackifiers that attract dust [Elektroda, DWAserwis, post #648488]
What’s an edge-case risk of over-oiling?
Excess oil can creep onto the rotor magnets, raise drag by 5–8 %, and cut RPM, leading to CPU temps rising 4 °C in stress tests [Tom’s Hardware, 2021].
Does molybdenum grease ever make sense?
A tiny smear helps only on badly worn bushings; MoS₂ particles fill surface pits and quiet the fan for a few months [Elektroda, DWAserwis, post #648488] "Use moly only when rattle is severe" [Elektroda, DWAserwis, post #648488]
How long will a lubricated budget fan usually last?
After proper re-oiling, low-cost 80 mm sleeve fans commonly regain 6–12 months of silent service at 70 % duty cycle [Elektroda, MIM ELECTRONICS, #648810].
Is hydraulic oil HM-68 suitable?
Yes. HM-68 is synthetic, thin, and has high thermal stability, making it a solid choice for high-load GPU coolers [Elektroda, Nemo, post #655919]
What tools do I need for the job?
Small flat-blade screwdriver, cotton swabs, 99 % isopropyl alcohol, precision oiler bottle, and optional nitrile gloves keep the process clean.
