||12-31-2012 06:29 PM
Just did it on my '90
Easy fix, it might differ slightly because mine is a little older, but they're pretty similar so here are the instructions for mine. First off get a new heater core, rockauto.com had the cheapest one for my vehicle. There are three nuts on bolts that come through the firewall that are 7/16th's in size, one is under the battery cradle. Take those off, easiest if you take the battery cradle off to see it, as well as a plug that goes to the blower fan. Disconnect the coolant lines that go to the heater core, you're going to want to drain some of the coolant out of the radiator before doing this to help reduce a mess (you don't need to drain all of it). Next disconnect the cables to the vents and pull out the heater unit from under the dash. Once that is out, take the screws off the back of the unit to reach the heater core, replace and re-install, easy! I did this in about an hour. Good luck!