Hard drive seems way too hot!

Yeah, I've been thinking about this for a couple of days.

Possible solutions are:
1.) Cooling the back of the iMac, I'm going to try with a 8 or 12 cm computer case fan (12v). Need to find a way to turn it on/off with the iMac
2.) Making OS X reconsider the lower limit of HD fan RPM (currently 1800 RPM). I believe that constant 2500-3000 would not make it louder (it's a small fan), but would help a lot for temp
3.) Modifying the internal air flow and/or HD casing

From simple to more complex...

Matevz:

As I understand your situation, you had a HD that failed due to unusally high temperatures(how high?). Apple sent you a new HD which has not been installed yet. You are currntly using an old HD. Where is it? In the computer or externally? I assume the old HD you are using is internally placed because you quote 53C for the HD reading and about 65 for the SMART reading. Then you talk about repositioning the HD sensor to the surface of the older HD. Not the new one because as I read your remarks, you have not installed the HD Apple sent you. The temperatures you quote are perfectly normal. Right now, my HD temperature is 53C and the SMART is 61. I don't understand why you think these readings are too high? Why are you moving a sensor around? You moved it to the surface of the HD. How did you do this? How did you attach it to the surface of the HD? There is no need to cool down your HD. The temperature of 53C is acceptable. Then you want to experiment with resetting the RPM of the HD fan so it will have a minimum RPM greater than 1800. I don't think you temperatures are too high and fooling around with RPMs is not necessary.
You do say: "I am about to install a new HD". Why don't you install it and see what happens. I would assume you have negated your warrenty. Depending on when you bought the computer, your warrenty period should be over soon. I suggest you get the two year warrenty extension if you can and let Apple take care of your problem which I don't think you have from the numbers you state.

dadof3:

The whining fan noise has nothing to due with the temperture of the HD. 55C temperature for the HD is fine. Where did you find that this is the maximum temperture? My HD temperature right now, using Hardware Monitor is about 53C and there is nothing wrong with that value.

Edward,

I have to day, I disagree with you. The disks are running too hot inside your iMac too.

The temperature does not have to be higher than allowed for the disk to fail prematurely. Seagate specifies 60 C ambient temp, and we are all chasing its tail. Disks will go down, as mine did.

I would not be discussing this, if the SMART disk temperature would be under 40 C, which is acceptable for 7200 RPM disks. 60 C is way too high for the disks to be reliable over the long run.

And I'm not saying that my situation is unusual. Actually it's common and that's what worries me.

I'm currently using the same, original disk (Seagate 160 GB, SATA). It was used in another server for about 9 months. I'm still waiting for the new one from Apple, so I can move this one back to my server.

You can reposition the sensor yourself and not void any warranties. It's just glued (with some kind of rubber glue) to the side of the disk. It sticks to anything you put it to.

As I said, I was unsuccessful in repositioning the sensor, since it made the system go up and down the temperature curve. It did, though, make the disk cooler for a couple of degrees.

Regards,
Matevž.

Ed, I have an 80gig hard drive in my rev A ( Seagate ST380013AS) with a max operating temp of 60C/ 140F http://www.seagate.com/cda/products/discsales/personal/family/0,1085,587,00.html and I am continuously above 130F. The larger HD"s, like dadof3, have max operating temp is 55C which is where I run normally. If you can knock 14F out of the HD with a small external fan, why not.

Dick

To Matevz et al:

I'm using Hardware Manager, processor at maximum, screen at the dimmest because of strain on my wife's eyes.
Over the last 7 days:
CPU: 33-76
HD: 22-55
SMART: 23-62. Obviously all in centigrade and not at the maximum temperatures all of the time and I have not had any problems. I received the computer during October 2004.
The temperatures you are all talking about are normal and I don't understand why all the worry. Ambient temperature varies depending on the season and with air conditioning during hot summer days. I can understand temperatures going up during the hot summer. But where is Apple in all of this? I would be on the phone right away. Anyway, that's my situation. Oh, prove to me the warranty is not voided by the disconnecting of the sensor.

Same here Ed, but Matevz hasn't been as fortunate and dadof3 has concerns which are real. Heat is the nemesis of electrical products and components and running close to, or just over, the max operating temp can not be doing anything positive for longevity.

Dick

Richard:

I have noticed, as I am sure others have, 4 threaded female connections at each of the four corners of the hard drive. I have always wondered why these are there and for what purpose. The obvious is to have the top of the hd drive covered. With what? Possibly a large heat sink? If one screwed an aluminum plate or whatever metals(alloys) heat sinks are made of over the hd, would this take care of the hot HD.
Tongue in cheek: Winter is here or coming soon. Just place the computer in front of a slightly open window and one would not need a fan.

Richard,

I mounted two large computer case fans on the back of my iMac all to no avail.

While the SMART sensor HD temperature does not rise to 63-66 C as fast as it did, it still gets there in an hour or two.

I'm again at 65 C, which worries me. How come you managed to cool it down?

Regards,
Matevž.

Matevz...I am responsible for some of this...as you say temps don't rise as fast...and they still get there in an hour or two...for me that was an improvement from ten to twenty minutes...plus a far quicker cool down >according to Temperature Monitor<

I have not had a 'heat' related issue..was just looking for things to run cooler..

Without modifying my iMac..the back of my iMac's case remains cool to the touch...in my mind that helps cool the inside...as TM shows..the CPU>HD>SMART will still heat up fully..depending on use...and cool down accordingly

...from my observations iMac's run warm...
dave

Matevz, I focused the fan only on the warm side (left when facing front) and concentrated the flow as best I could with out interfering with the discharge port. The results were positive because my temps (HD) dropped approx. 9C and stabilized. I am going to get a fan like Dave Stowe's which appears to operate like a blower and can be better concentrated. The key is to cool down the casing and allow the casing to act as a heat sink. The fan was affixed to the computer at all. It was just a small desk fan. How did you mount the fans to the back of the computer?

Dick

Matevz, I just put a smaller desk fan behind the computer ( the other fan had a blade like a P51), focused it down so as not to interfere with the discharge and temp. monitor is giving me the following readings:

CPU T 62.9C/145.3F
HARD DRIVE 49.5C/121.1F
SMART Disk 48C/118.4F

Dick

Richard,

Your temps are much lower than mine.

I mounted the fans directly to the back of the iMack. I actually mouted two fans, one on each side.

Temps will not go down. I'm still in the same range. I have to say it again that this does help the time before HD goes 65 SMART C. It takes longer but nevertheless, still gets there.

Still, now everything is working fine, thumbs crossed. It just worries me.

Regards,
Matevž.

Matevz, my fan is not mounted to the back. It is a simple table fan (small) setting on the desk and I direct it only at the lower right side of the rear when facing the rear (warm side) . It works great. I have not attached anything to the computer.

Dick