So the mechanic wants to charge me 1000+ to replace the heater core on my 2000 s10 ZR2 pickup 4wd. Does anyone have detailed directions on how to replace it myself? I know it isn't a light undertaking but am willing to try. Thanks.

Go to a parts house for a Haynes manual and it will give you directions on how to do this, I did it on my 92 s 10, it was hard but I did it, way cheaper than $1000, just take your time good luck