Heater Core Help ASAP


Jun 10, 2001
I'm going to take on this tomorrow afternoon. I know I have to remove the top of the air condition box to get the heater core out. Now what are some tips and tricks some of you guys know in help of the process of doing this? I have coolant in my floor board and it leaks out into the down pipe sometimes also, that is heater core correct?
Got my core at NAPA for $17.00 2 years ago. Clean up all the black goo along the firewall first. Lotsa little bolts and one hidden WAY down there after you remove the screen. Be sure to goo it all up real good when done, or you'll have rain leak along firewall. Be sure to burp the cooling system good when done. I've started drinking. 2nd easiest core I've ever replaced. !st was an explorer - 2 clamps, 4 bolts and it drops out. At least you don't have to remove the damn dash.
www.gnttype.org has the procedure how to do it that is pretty clear and straightforward.

If you haven't had the heater core hoses off in a while get some new ones first. You might have to cut them off like I did.

Or dig up the special tool that is supposed to be able to loosen them properly. :)
See my problems I'm having. See starter name of COPO for a 195F Tstat question.
the last screw towards the back on the passenger side was coverd with something i guess like undercoting or whatver but i had to pick at it to reveal the screw untill i can take it out .. remember that one or youl be wondering why it wont come out i recleaned the serface and resealed the box with black silicone came out nice.. if your replaceign the heater core hoses aswell try and get 90 degree bend hose if you get a straight hose and try and use it it will creze and probably get no flow. i changed my heater core a month ago came out really well .. the heater core cost 17 bucks from autozone. :)
Make sure you order your heater core from GM. I had a heater core installed from a Rad Shop and it didn't produce any heat. I don't know the internal core differences but I have lots of heat now. The non GM core only produced 87F at the front dash vents on hot/heater with and without a piece of cardboard in the grill. In the city the GM core produced 122F and the highway 124F and it I step on it it'll read 146F. I was in a 2 yr old Olds Alero and in the city going 30mph it gives off 146F.
Heater Core

The GM replacement heater core is not identical to the original, it is a Delco replacement. I bought one from Pep boys and it looked closer to the GM original then the Delco replacement. It also cost around 12-15 bux.
There must be a difference in the insides. If you don't want to yank it out twice then get a GM one. This GM one must only cover the GN. Other brand cores probably covers more cars than the GN. It's up to you. Don't say I didn't tell ya so, if the non GM core doesn't work.
I fixed my Heat!

I was having the same problems as you were with your heater. I replaced the therm, heater core , bled the system--No good.

I read the Manual and it lead me to the problem. The cable keeper on the heater cable had broken and this prevented the temperature mixing door from closing. I tie wraped the cable under the dash to the metal support and now the heat drives you right out of the Car!!
I just changed my heater core last weekend and I'll tell you that most parts stores have them mislabled. The 86-87 Turbo Buicks take the N/A Regal Heater core. The parts store have the 84-85 Turbo Buick heater core listed for the the 86-87 cars and they aren't the same. The 84-85 cars have a slightly different inlet and outlet. Make sure you take your old heater core to the store and compare before you buy the wrong one. In fact, the 84-85 core is twice as expensive too.