Changing the core should not be attempted by anyone. You have to remove your dash as well as work under the hood. Most mechanics try everything to keep from replacing the core. Anyways, once you have dash torn apart, (your core will resemble your radiator) drain out as much fluids as possible, disconnect the hoses under the hood and then begin the dismounting unit. Reverse the procedure for replacement.
If your heater is simply not producing heat in the cab, try flushing your system and replacing the engine thermostat.
How to change out the heater core on a 1994 Chevy Blazer?
Its way to complicated to explain here,go to the parts store and pick up a chiltons or haynes manual.This manual will give you all the info you need to do any job including rebuilding the engine if you need to and they are fairly cheap.Good luck.
How to change out the heater core on a 1994 Chevy Blazer?
Ok im doing mine right now to, buy the book first, then you need to pull out the glove box, ash tray, and disconnect all the cables leading to the heater box under the dash, then you get into the motor compartment and where the heater and air conditioner is you should find maybe 3 nuts that are around the air conditioner or the heater box, don't touch the bolts, one might be a ***** because of the inner fender, and you might need to lower that to get to it, then grab the heater box from the inside and lift and pull it out,
open it up and change out the heater core, then back together, I tried to make it sound easy but it really sucks.
