Heater Core

Can anyone please tell me how to change the heater core.
Can a person tell by looking at it if its no good , thanx!!

I think usually if its bad you would have antifreeze smell or moisture/steam in passenger cabin. If cooling system is mucked up over the years maybe it could also have deposits and less heating ability

I actually have NO heat, I got the thermostat changed last week, and that wasent the problem. Any Ideas?
Theres no smell of antifreeze in the car.. Thanx

Low coolant level 'might' cause lack of heat also. Have you changed or added coolant lately? And the coolant system may have to be bled of air to work correctly, I don't know if yours falls into this catagory or not.

Also, if you turn fan on high, do you get proper amoumt of airflow where its directed (floor, defrost, wherever)? If not the little doors that direct air flow might be messed up.

I see from your profile you have a 93. If your thermostat is ok and your car is not overheating or running too cold, it is a damper door. Pull the glove box out and the passenger side kick plate at the bottom of the dash. Follow the cables coming from your heater controls. One of them has popped off. You will find a rectangular plastic piece in-line of the cable that attaches to the one of the diverter doors that directs heat. I had a similar problem years ago. Cost me one hour labour at the dealer for a two minute fix.....it took them that long to diagnose. By the way, it is the cable that connects to the hot and cold dial...yours came off and is stuck in the cold mode.