Spent around 1 1/2 hours replaceing the heater core after the old one blew up. I was carefull not to damage anything but it seems my hvac controls have no vacuum at all. I checked teh secondary vacuum lines under the dash that i could see (with the dash assembled) and checked the main line in the engine compartment and that one seems intact. Still a no go. Does the main line that delivers the vacuum run above or around the area where the heater core is? Anyone know what else i could have disloged, broken, or disconnected that would kill the controls? I guess tommorow ill pull the dashpad off again and have a more thorough look.

BTW, i didnt dissasemble the dash, i just removed the enclosure around the heater core itself.

 

hey dude, ya dislodged a line is all, pop the dash off and look behind the blower box and behind the controls......youve helped me now I help you

 

thats what i figured. Probably the main line that feeds vacuum got cracked by accident. Hopefully i can find the break. and hopefully the break isnt in that rat's nest of lines behind the hvac controls.

 

probably not cracked, just dislodged.....in the nest....ya know its just gotta be that way...oh and by the way, how ya like the holley??

 

Did you make sure the flap door was properly set in the two holes for it to pivot in?

I changed my heater core a couple of months ago. My friend did the pass side while I did the driver's side. He didn't make sure the **** of the flapper door where lined up with the holes in the heater box. I could move the vent controls all over the place but the air always blew out the dash vents.

I was able to get in there without pulling the whole frikkin dash off again, thank goodness.

Of course what 25thanniversZ said is very possible. I just figured while you're in there, may as well check both possible problems.

 

thanks... i was thinking the same thing. Probably the damper was jammed. The case never really did seem to line up perfectly so thats probably the problem.

thank *** i left that top bolt out...

 

I need to change the core in my 88 GTA. Not looking forward to it. I think I may be able to get into it without pulling my entire dash. I heard there is that screw up top that is a b****. I was thinking of removing the passenger seat just to give me more room to work in there. You got any tips?

 

yes please give tips LoL i need to do mine too my on 91 firebird

 

Keep all the screws seperated and organized. Use and air ratchet or an electric srew gun if at all possible. It'll speed things up A LOT.

Don't expect it to be easy or to go fast. That never happens.

 

hey AJ how about i come down there and you help me :-D
lol

 

one thing to do is have a ratchet with extensions and a u-joint on hand. The first few bolts on the cover will be easy to remove but the last one is a real bitch... Like, even harder to remove then the two tranny bolts next to the firewall. Remove teh dash pad, speaker frame, and ecm to give yourself room to take it out. The next thinbg to keep in mind is observe the linkage next to the heater core that contols one fo the dampers. Alot of people have broken this linkage because its so hard to get the heater core and the plastic frame that supports it past. Mark the plastic carrer of the heater core and put a small notch to help get it past that linkage when you go to install. The final thing is getting the fittings back into the firewall. Line the heater core up as best as you can and go around to the engine compartment. You should be able to see the fittings on teh heater core through the holes. Take a screw driver and gently line the fitings up with the holes in the firewall. Go back inside the car and press the heater core into place. It should slide right in. All thats left is bolting things back together. Heed AJ's advice and make sure that door he was reffering to is lined up.

 

as for the top screw, i lined the socket up by feel and used the ratchet to break it loose. Youll really need work from up top. I found it easiest to line up the rachet. After I got it loose, i jsut left the stocket on the bolt and backed it out the rest of the way by hand. Be patient, it will eventually come out.

 

nope, wasnt the door. Those where lined up fine. Its most likely the stupid hose. I guess ill have to run in another hose to feed it vacuum.

 

*beats self over head repeatedly with blunt object* OMG i cant beleive it... After taking all the vacuum lines of the controls and testing each circuit with a vacuum sorce and finding everything to be working i found out the vacuum port on the tbi that im using doesnt have vacuum. Of all the things to be wrong... I guess holley has some strange ideas about what a vacuum port really is. oh well, at least it all works now.