I started smelling coolant in the vents when the heat/air was on and the inside of the windshield frosted over late in the winter. I took it to a shop they said it was the heater core and it would cost 900 to fix, I don't know much but I thought that was pretty damned high. Is this something I can do on my own or am I going to have to pay the 900?
You now know not to take anything to that shop again.
Not seeing the year in you signature, I'll tell you the 1992 + are easy. Remove the glove box. Remove about six screws off the heater box cover. Disconnect the hoses of course and it comes right out. Put some RTV around the new tubing at the firewall to seal it.
That shop is either: A) Completely ignorant or B) A bunch of scam artists.
My Chrysler LeBaron had to have been thee most difficult heater core replacement I've ever known. The entire dash had to come out. The steering wheel had to be disconnected and dropped. Center console and shifter had to be removed. The visors had to be removed! (Visors were covering A pillar panels, which were covering the side panels, which were covering the dash screws, etc, etc.)
A shop wanted $600 - $700 to do it. I don't blame them. It took me 8 hours in a professional shop to do it myself.
My Bronco.... It took me 30 minutes and a wrench.
You remove the glove box. Undo the bolts holding the heater box to the outside firewall. Remove heater core, put in new heater core. Tighten bolts back down. Replace glove box.