Replacing this heater core is harder than I expected.

[BuffaloRider]

I'm in the process of replacing the heater core in my 1990 grand marquis. I've unhooked the neg battery cable, drained the coolant and removed the two heater hoses. Then it says take off the three nuts below the wiper motor... there is one nut that is next to where the heater hoses attach to the firewall/plenum then two more on the bottom, is that what they are talking about? Either way I got those.

I took off the wood trim on the front and around the instrumental panel/speedo and crap and also pulled that back after dropping the steering wheel (and unhooking the shift indicator). I've got the bolts under the kick panels too. This is where I'm getting confused.

I've read 86vickylx's heater core write up many times and there are many differences in the dash between the 1990 models and earlier models that must make the process very different. I say this because I can't remove the top of the dash pad as easily as it seems to be done in that write up. I can see the heater core housing from behind the glove compartment and even jiggle it around a little, I feel so close yet so far away.

If anyone can offer me assistance with this I would be very grateful because I'm trying to have this done by either monday or sometime this week. like that's gonna happen. I'll come back with more specific questions but in the meantime I'm gonna go see what else I can do.

[BuffaloRider]

Questions

"disconnect two vacuum supply hoses from vacuum source. Push grommet and vacuum supply hose into passenger compartment." I have no idea what the vacuum source is or where these two hoses are. Wait a second, is that the cylindrical vacuum motor that's attached just above the floor air distribution duct?

"Disengage the temperature control cable housing from the bracket on top of the plenum. Disconnect the cable from the temperature blend door crank arm."
I can't really get to the top of the plenum except for near the glove box so I don't know how I'm going to do that or what I'm looking for.

I just now found the temp blend door crank arm in my book, it's just on the bottom of the air inlet duct assembly, right?

Thanks.

[BuffaloRider]

Im so fucked. I wish they had more pictures in my manual.

[gadget73]

The 90 dash top does not come off as far as I know. Exactly how you're supposed to get it away from the firewall I have no clue. The official shop manual I think has you drop the air plenum assembly out and bring the heater core box out through the bottom, or at least thats what it was on the 80s models. Never spent any time inside the dash of a car that new so I really can't help you much.

The vacuum source comes out of the center of the firewall and connects to the vac tree right behind the motor. Don't know why this needs to be moved, or at least I never had to do anything with it on my car. My lines were melted off and repaired though so I probably have more slack.

[t65neon5]

its been awhile, but I was at a shop that was replcing the heater core on a 91 grand marquis, and if I remember correctly they had the WHOLE dash removed to do the job (they unbolted it and pulled it back a couple of feet to access everything, cant say if they were doing anything else to it at the time, I was just delivering the heater core and took a look while I was there)

[BuffaloRider]

Thanks gadget for the location of the vacuum supply, I know about the vacuum stuff attached to the firewall behind the engine I just have to look for the two hoses they're talking about from the inside.

t65neon5, please don't tell me that lol although that's kind of what it looks like I have to do because the dash pad is attached to pretty much everything else. I need help.

[87gtVIC]

I always pull the dash away from the firewall in my 87.....




Good luck mang.

[BuffaloRider]

hmmm... this is getting confusing. The manual doesn't specifically say the entire dash has to be pulled away but then again they want me to get to things that I'm pretty sure I can't even see unless the dash isn't there. people seriously did this in like 4 hours? Am I really that clueless?

and I definitely can't get to the vacuum supply from the inside. I just wish I knew where these two vacuum hoses that I'm supposed to be pushing into the passenger compartment are.

Thanks

[gadget73]

If you find the vacuum tree, there should only be one (or three, if its ATC) lines that go through a grommet right next to the vac tree. One goes to the tree itself, and if its ATC, the other two go to the thermal blower lockout thing in the heater hose. Its within 3" if memory serves here, and its the only vac line that goes through in that area.

[t65neon5]

I always pull the dash away from the firewall in my 87.....




Good luck mang.

yup....that's what I remember seeing (ok it was the newer dashboard , but you get the idea)

[jaywish]

are you using an OEM Ford manual? Or a chiltons?

[BuffaloRider]

ford manual, not a chiltons. The instructions in my manual are practically the exact same as this http://www.fixya.com/cars/t12531097-..._wont_come_out

my time has pretty much run out for the day, it's starting to rain a little and I'm stumped I still have no idea what two vacuum lines I'm supposed to disconnect, not to mention the countless other things I'm supposed to disconnect, most of which I'm unfamiliar with. I'll get my phone up and running tomorrow and hopefully take some pictures.

If I knew what to do I'd do it. Thanks for your guys help, I'll get more into it tomorrow.

[Ike Clanton]

I didn't have to move the whole dash on my '88 Lincoln.

[Lincolnmania]

wish i could help u mang

[BuffaloRider]

I found this after a handful of google searches


so now I know where the temperature control cable is, I'm pretty sure I saw it when I was down there. And I have to "disconnect the cable from the temperature blend door crank arm" which is 4 on the diagram below and I should be able to see that from behind the glove box.


So I should have step 10 covered. In step 11 I have to "disconnect the vacuum jumper harness at the multiple vacuum connector near the floor air distribution duct" so it's off to find out wtf the vacuum jumper harness and multiple vacuum connector is and looks like.

I really wish my manual wasn't missing the page with the "V" section of the glossary... just my luck.