CPU B Termperature as high as 176 Degrees Farenheit, Fan Very Loud

Look in Activity Monitor (in /Applications/Utilities) for any processes that seem to use way too much CPU. Then quit them, and if you can't, list them here.

Also, some processes don't show up in Activity Monitor. iStat Menus shows some of those.

Yeah.. one suggestion: GET NAP MODE! You can get chud tools 3.5.2 and install nap mode. You will be amazed at how much your cpus will love it! Although, my mac has never ever gone above 130 degrees, right now with nap mode enabled my processors are around 95 degrees fahrenheit.

Also, get a 120MM fan and mount it on the roof of the optical drives, facing towards the back - bye bye hot air! This will help also.

Get rid of Jaguar and move to TIGER. Get nap mode, and watch your temps go down!

Hi

The main fan getting louder suggests it and its response to increasing CPU temperature are both OK.

Have you checked the air inlet (lower front of case), the main fan, the heatsink and fins, and the rear grille for dust buildup?

Is there any possibility that the heatsink isn't properly seated on the CPU?

Can you check if both power supply fans are running?

Best wishes

John

Wow, that's HOT !!!
Do all the fans spin ?
There's fans in the power supply area too.
Something has to be wrong there..
At least consider a quick ($10-$20) PCI slot cooling fan.