busy/noisy fan?

[strawbale]

recently noticing the fan becoming noisier and seeing that the fan speed quite often goes beyond 3000 rpm.
For instance at the moment, when only Firefox and Mail running (so CPU about 90% idle), I'm reading the following temperatures (with 22.7° C in the room):
HD 42°
CPU 53°
CPU heatsink 45°
Ambient 43°
Northbridge 1 47°
Notrhbridge 2 47°
fan at about 3300rpm

Are these normal/OK readings?

PS: mid-2007 2GB 2GHz model

[mooblie]

Blocked air vents? Might be worth taking the top off, and blowing out all the vents to ensure they're clear?
_________________
Martin at HeadSpin HD now on Blu-ray

[strawbale]

I'll check that out (tomorrow) - thanks!
_________________
Mac Mini mid-2007 2GHz 2GB 120GB