Hi Chris,
I recently uploaded a repair guide for replacing the DC-in power jack of an ASUS 1001PX, which also shows how to remove the cooling fan. You find the guide here: [guide|96332]
I suggest that you remove the fan and clean it first. Sometimes dust that has accumulated over time can be the issue. Or just buy a new fan, which you find here: https://www.ebay.com/sch/i.html?_odkw=1001px+cooling+fan&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.X1001px+fan.TRS0&_nkw=1001px+fan&_sacat=0
Steffen