How much can high temperature contrib. to KPs/freezes??

Question

So I've been using G4s for years, my first--my beloved 2000-model Ethernet Firewire--was my introduction to modern desktop Macs, and served me well for nearly 7 years, until the depressing crash of its internal/boot drive necessitated I move on. A family member who was upgrading themselves gave me their old 2002-era noisy Mirrored Door G4 recently, and I in turn upgraded it to the last installment of Tiger (I hope that it'll tide me over until I can upgrade to a newer Powerbook or iMac running Leopard within the year).
However, with the inheritance of this newer G4--and in particular, upgrading to Tiger--I was introduced to a variety of new problems: freezing, and the dreaded Kernal Panic warning. I've been trying to troubleshoot, but it's difficult because there are a lot of variables.
However, one possible factor that I don't want to rule out is temperature. Every time I pull this G4 out, it's running really hot (which doesn't seem to make sense, since as LOUD as the fan is, you'd hope it'd be working). So for all I know, part of the problems could simply be due to this thing overheating. Is that likely? I had been assuming it was a RAM problem--incompatible/insufficient--and had been considering adding more, but don't want to do so if it's just going to get fried...
I remember hearing that Apple offered a fan & power replacement supply plan for this particular model, but have NO idea if I can utilize that now. And THIS website says it has a firmware download to help reduce high fan speeds, but I think that was only while using OS9...
http://docs.info.apple.com/article.html?artnum=120171
Do you have any ideas? Any suggestions on WHERE to place the computer, additional fans/devices I can use to keep it cool? (assuming that this fan/power replacement supply is unavailable).
Help!!!

Answer 1

Thanks again, I guess I was just naively overlooking the 3.5.2 package... duh.
Yeah I called Apple Care, they were actually fairly helpful, and suggested that the 256 mb RAM alone would be enough to run Tiger, so less and less am I suspecting that RAM is an issue...
That Temperature Monitor program was really helpful too, showed that my computer was averaging around 57-58 degrees shortly after activation... yikes. Even after I put it to sleep for an hour or so, after I reactivated it, it shot back up from the 31-32 degrees in its inert state to 50 or so.
But I Deinstalled (fortuately wasn't anything to deinstall), and the Hardware Tools switch did show up in Preferences, like you said. Fortunately, even WITHOUT changing a single one of the settings--well, that's not entirely true, I switched it to Dual CPU, which my computer is--the temperature seems to be remaining around 43 degrees or so, so already something's working. But, do you have any suggestions on how to further adjust it? I ask, because I see pull-downs for the L2 & L3 caches...
Also, what about any of the other programs that showed up in the CHUD folder--BigTop, MONster, Saturn, Shark--can any of THOSE help me?? At the very least, the Spindown HD one in Hardware Tools looks relevant....
Anyway, if you have any further suggestions on how to help keep this computer cool, I'd really appreciate it. Though I may not currently be up to the task of doing anything like that PCI slot fan, or the thermal compound, I'm not adverse to learning more (certainly troubleshooting this whole issue has already been pretty educational). That xlr8yourmac had some interesting suggestions, but only a few of which I think I'd be qualified to try (certainly any soldering is outside my capabilities, and I'm not even going to TRY to touch on the guy who irrigated his G4 with cool water...).