It is under the dash board and it is extremely difficul to change. Shop labor and parts will cost you aroud $350.00. I just had mine replaced. It can be done, though. Took me six hours, three of which were the stupid dash. You'll see the two hoses in the middle and the bottom of the firewall.
how do you get to it
Most likely your heater core has gone bad.
To replace most heater cores you have to remove the dash on the passenger side.
please tell me how to remove the heater to get too the heater coil
i changed heater core in a 1995 Oldsmobile achive you have take your dash under neath just about the centercloser to the right also you have jack up your car theres two hose you have to take off its har get them off and on its alot of work it takes time to do it right a 1989 grand am heater core will fit it as long as it has a 3.1 Fred zeestraten
How do you change the heater core on a 1989 Oldsmobile Cutlass Ciera? or where can I get the Info on replaceing it
The question you ask is too involved for a proper answer. you need to go to a car parts store, and get you a repair manual for your car. They cost about $16.00.
I am assuming you mean there is volume from the blower but it is cold. If so, First check your coolant level, if it is low the first thing to empty is the heater core. Check this and get back.
how do you replace a heater core in a 91 Oldsmobile 98
you need to replace your heater core.
I have used radiator stop leak before in my 1996 Olds Achieva SC with the V6. I put it directly into the coolant resovor. It went in fine for me. This did not give me much help though. I would not recommend using stop leak. It will clog your heater core and then you will have more than the radiator as your problem. Fine a new radiator and replace it that is the best advidce i can give you.
It is about a 3 hour job. It would depend on the hourly charge of your local shop, plus the cost of the heater core. Which I think is around 30 bucks.