Thanks for the follow-ups. I'm still looking, but will favour a
thicker fan as you recommend. Presumably the fan would always come
with its own nuts or screws?
No.
Typical fans marketed and advertised towards "PC" use are as
often really low quality junk, stuff the seller makes a
maximum profit off of as it allowed most markup possible.
Decent brands of fans do not generally come in any kind of
kit form with screws or anything else. At most you would
seek a fan that thas the correct connector for the
motherboard. Look at the current screws to determine their
size, as you might be able to reuse those (on many fans,
there are tabs rather than a deep channel hole such that the
screw does not extend all the way to the top edge of the
fan, only to the bottom flange so the same screw used
previously "might" work (I cannot see it so I cannot be sure
of this). If the original screws can't be reused, note
their diameter and pitch and possibly you have a few spare
screws around the house or get a dollar pack at the local
hardware store.
The existing ones are nuts, which screw
into holes on outer edge of h/s. I've seen other integrated units
which appear to use self-tapping screws, and sometimes I understand
these 'screw' merely into the space between vanes?
I don't understand what you mean by "nuts". Well, I know
what a nut is but I'm not visualizing it on a heatsink.
If you mean that the heatsink has holes drilled into it, and
in these holes there's a tapped sleeve that another machine
screw threads into, you might do as I suggested above, see
if the original screws work and if not, grab compatible
screws at the local hardware store.
So do essentially tap into (or just crudely cut a few
grooves into the sides of) the vanes. It is possible to
mount a different shaped or sized 'sink like that but i was
anticipating that if you're choosing the same diameter fan
as the original, the holes should still match up to the
current mounting points so you would be able to use exact
same mounting method with the only potential issue being the
length of the screws?
Re the 'adapters' that I see mentioned, are they to adapt 60 mm to 80
mm for example?
Those are often more trouble than they're worth, as putting
the fan further away from the 'sink means it has to maintain
pressure on a larger volume of air which reduces the flow
rate almost to the point of no benefit over a smaller (but
still thick) fan.
Ideally (if the height isn't an issue) you should choose a
fan that's 60mm x 25mm, and fairly low RPM, perhaps around
2300. For example,
http://www.dansdata.com/images/coolercomp/ys7200400.jpg
Above example is only of the size proportions and mounting
flanges, the particular fan model shown is a very high RPM,
far too loud, while you'd be looking for one closer to 2300
RPM or about .12A, perhaps slightly faster if your 'sink is
very poor, you had poor case ventilation or a very warm
ambient (room) temp at any time during the year.
So with a fan like that the screws only go through the
bottom flange into whatever the 'sink provides as the
mounting point, as in the following picture it's a plastic
frame on the tines but otherwise it might just be directly
screwed into the metal or another structure,
http://www.dansdata.com/images/coolercomp/teyst400.jpg
If the necessary mounting method is still not clear you
might seek a good online picture of your 'sink (including
the mounting area in view) and link to it.
Wouldn't a heavier fan (either through larger diameter and/or greater
thickness) impose extra vibration stress on the CPU?
There will be a little more leverage against the CPU but the
'sink mounting clamp is plenty strong enough (assuming it
isn't defective). Vibration is typically due to imbalance,
if any fan is vibrating very much it is a sign that it's
either worn onto the point that it needs replaced, or very
poor quality/defective and shouldn't be used as new.
With the thicker fan, you move more air per RPM and can
lower the RPM (choose fan with lower default RPM if you're
not inclined to find a manual or fan-controller method of
further control over the speed) so that with this lower RPM,
there is less vibration, and much slower fan wear so even
given a similar low-quality fan to the one you've had
failing, it would take longer to wear out the bearing (all
other things being equal).
Always use at least 25mm thick fan on a CPU heatsink
whenever possible, with either a renowned sleeve-bearing
(like on a Panaflo, Papst, or rarer on other makes of fans)
or a dual-ball-bearing system. A fan that simple says "ball
bearing" is often not sufficient as many low quality fans
try to market this when they actually use one ball and one
sleeve bearing which can be worse.
It is not common to have a CPU fan failure when a good fan
size, RPM and quality is used at the start. Unfortunately
you have been a victim of a poor engineering or
bean-counter's decision to chose the wrong fan for that
'sink and so now you've need to fix their mistake.
