Question edited for clarity and typo 'weephile'.
Question moved from Misc to model category.
Screeching is dry metal on metal abrasion. Take it all apart and get some water pump grease on the shaft or replace it completely.
Seems to be a known issue
https://www.google.com/search?q=2002+Yamaha+YZF-R1%2C+coolant+leaking+from+weep+hole
..