Weird Temperature Spikes

Computer details:

MacBook 3.1, 13"
2 GHz Intel Core 2 Duo
4 GB RAM
Mac OS X 10.6.5
Western Digital 320GB 5400 RPM hard drive (I believe this is a Scorpio Blue)

I'm trying to diagnose my girlfriend's recent fan/high running temp woes.

I was sitting here watching the computer. The temp is at 51-54C. Activity monitor is open. The process using the most CPU is "Temperature Monitor Lite" at 1.1%.
Suddenly, for no reason I could discern, the temperature read as 92C. I didn't see the temp step through the temperatures. It seemed to me, although I wasn't watching it every second, that the temp went from 54C to 92C instantly--it certainly happened in under 15-30 seconds. All the fans kicked in, and brought the temp back down to the 60s quickly. And then it jumped up again, engage fans, back down to normal temps.

I'm trying to recreate the problem with little success. Going into "Disk Utility" and running "Repair Disk" caused the temp to shoot up into the 80s and activate the fan. Running "Disk Permissions Repair," it ran in the mid-to-low 60s, even though there seems to be a lot of read/write access on the drive (my initial thought was that this was somehow related to accessing the hard drive.)

Any ideas where I should start to begin diagnosing what the problem could be? Is it really possible for the CPU temp to spike from the mid-50s to 90-ish in a matter of seconds?

Oh, wait, I hear the fan starting to whirr again, even though I'm idling here. Looks like I didn't click on "All Processes" in activity monitor. It appears there's an mds (Spotlight) process that pops in from time to time at over 50%, and a lot of disk activity with a corresponding temperature spike, although it's not reaching anywhere near the 90s right now.

 

Just saw the links in the other overheating thread. I will look through them and see if any apply to this computer.

 

Thanks. For the moment, the problem seems to have gone away, given the advice in the other threads. I'm not sure which of the following did the trick, but I:

1) Reset the PRAM
2) Reset the SMC
3) Installed that fan regulator program to keep the minimal fan RPMs at 2500.

I suspect either 1 or 2 did the trick.