Heat issues on '85 GT

[2BADSTANGS]

So, I'm working on my brothers "85 GT. The heater will only blow warm air, not hot like in my 'stangs. I've checked the function of the heat/ cool selector flap in the heater box and it seems to be functioning correctly. The climate control box is not leaking air. The heater core was replaced recently. The coolant seems to be flowing through the heater core as it should. Any suggestions?

 

[93 LX]

most likely the heater flap is not being opened all the way. Check it to make sure that the cable is indeed moving the flap all the way open.

 

[2BADSTANGS]

I checked he cable, its moving the flap from the open stop point to the closed stop point. Is there any way to look inside there to verify that it is functioning without pulling the whole heater box? (I've had to do 2 heater cores on my 93'gt. PITA.) Dunno if it matters, but his had factory A/C.

 

[2BADSTANGS]

Problem solved... Apparently my brothers GT fell victim to the notorious "fox body heater core gnome." However when I pulled the old one out, the fins on it looked like they were manufactured incorrectly, so no air could pass through. Mabye a bad one from the get. Did I mention how much I LOVE the placement of the heater core on these foxbodys? (Thats the 3rd one I've done.)