Dell cooling fan

I need to buy a replacement for a Dell cooling fan that's squealing for
a friends Dimension 2350. I'm A+ and can replace it myself but Dell
website is deadend for finding the part. I just want to get my hands on
a probably $10 fan that's compatible. I build my own PCs from generic
parts and proprietary is a four letter word to me. I'd also like to
get a tech diagram of the 2350. Advice? Thanks for any info.
Bo

http://support.dell.com/support/edocs/systems/dim2350/

Case fans should be standard; measure the current fan to confirm. You
could also try a drop of light motor oil on the fan that's squealing.