Since you're ready to replace your clutch fan, get a can of STP engine treatment and a syringe with no needle and fill your clutch with 15-20ml of syrup. For the price, it's worth testing to see if you can extend its life.

Toyota sells 18ml blottles of silicone fluid in 3 variations of... uhh... whatever centistokes describe. It's about $15 per bottle. Part numbers are in the archives.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD