I've bought my Acer Aspire 5570 with T2450 Core Duo 2.0 CPU and Intel GMA950 Video 1.5 years ago and back then I wasn't into fiddling around with it, plus I also had warranty on it and didn't feel like voiding that.
But lately it has been pissing me off, because if I actually use it for anything other than browsing text-based web pages it gets hot. And if put under max load after 10minutes you run the risk of burning your hand if you touch the laptop underneath (75C according to RMClock Utility).
But now, since warranty is long over i decided to see what I can do to improve cooling.
After spending a good amount of time looking for service manual I found one on ed2k network and set it download. Eager to get the things rolling I took it apart blindly (wasn't hard at all) and of course, right when I was done with the last screw the service manual finished downloading... *sigh* (To save you from the same fate I've uploaded the service manual at the end of this post.)
I have cleaned the heatsinks (there wasn't much hair, since i used to blow it out with compressed air occasionally), reapplied thermal paste and then I noticed that about 3/4 of air vent on the bottom of the laptop (where air gets sucked in for cooling) was blocked by a piece of removable plastic, whereas the fan was big enough to use the whole vent.

So i got an idea. I removed the plastic and air-filer net to uncover the whole vent. And then i realized that I'll need to get a bigger piece of air-filer net in order to cover the whole vent. Luckily, I remembered I had an old Dell damaged laptop base and after digging through lots of old PC junk i was able to uncover it. Luckily, the air vent on it was also covered with an air-filter net and it also was big enough to fit on my Acer laptop. It took me about 5 minutes to tear it off the base and after cutting it to the right size I placed it on the sticky residue left from old net on Acer and ended up with this:

I made sure it attaches to the base of the laptop securely and quickly assembled the laptop back. Turned it on... And i was amazed at how much air was coming out of the vent. It had nearly blown me off chair
So i decided to put it under heavy load... I set foobar2000 for encoding 1,000 mp3s in two threads and went to get a snack. When i came back after 10minutes, I touched the laptop on the bottom and on the keyboard and for a second I actually thought that I forgot to start the encoding process -- the temp of the casing was only ~5C above room temperature!!! Even though RMClock reported only 6C drop as compared to temp before mod case was MUCH cooler. I guess that with that plastic blocking the vent there was not enough air for the fan and without enough cool air coming in hot air was trapped inside the laptop, heating up the case.
After i stopped the encoding (there was no load on CPU now), the temp went from 69C to 48C (according to RMClock) in 30 seconds. I was amazed, lol.

So yeah, I hope some of you still have those Acer Aspire models laying around and you might find this information useful.

Cheers!

PS: It might also be of help to remove plastic sicker from vent on the memory cover, but don't forget to add some sort of air-filter net (just so that something like a paper clip doesn't get in and shorts the motherboard).

SERVICE GUIDE/MANUAL FOR ACER ASPIRE 3680 5570 5580.
AT YOUR OWN RISK
DOWNLOAD rapidshare.com (yes, it includes dissassembly instructions)

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Great tip. Admins :Chance of making this a sticky or put in a self-help area???

Another brilliant DIY idea in laptop cooling.

cheers ...

I'm using Aspire 5572 with process T2300E, i done the same mod as above, but it cause the machine unstable, final found out that the GPU is overheated, that's mean they are purposely block to allow the fan to suck inside notebook heat also to prevent the GPU overheated. anyway, i had change back to original & everything it work fine. So do be careful on this lol.....

iv just found the same thing on my aspire 7000...the grill was blocked off so i too the cover off but that stopped the flow of air from cooling the front of the mobo and i got hot and faulted.

it went back to normal after i covered the grill back op and returned the flow of air to normal.