1968 Cougar Heater Core Replacement With AC

Does anyone have a diagram or picture of how the heater hoses go on this car. When I got it, the heater core was bypassed. I am in the process of taking out the Heater box (any tips would be appreciated - does the center console have to come out)
I will also have to disconnect the AC lines, but was not sure of which nuts/bolts need to come off in the firewall.

The car was an original 390 car, but now has a 289 in it. I will be installing the 390 back in the car this winter (and converting it to a 4 speed). Are there different hoses for the small block vs the 390

Thank you

The factory shop manual gives a great step - by step procedure for removing the AC / heat box and shows proper connections for the hoses too. You don’t need to remove the console since you will leave the defrost / fan assembly in place. However, removing the console makes it easier, as does removing the passenger seat.

There is only one set of hoses regardless of engine size. If you don’t already have one you will also need a water control valve.

Making the heat / AC system functional is heavily dependent on the vacuum system operating properly. In your Cougar this means the headlights have to function properly, and the vacuum reservoir in the RH fenderwell must be functional too.

I have the 68 cougar shop manual. The one I have as about 10 steps, but does not have too much detail or diagrams on how to run the water lines to the water control valve, and I will need to test/check to see if this valve is working.

How does the heater core box slide out, i have all the bolts and hose disconnected and the center console out. Do I have to do something to disconnect it from the center housing. I am able to move the right side back(passenger side), but cannot disconnect it from the center housing

The best diagrams are actually in the “Body Engineering Electrical” manual. I picked a full set of the assembly manuals up from WCCC and they answer a lot of the questions that the shop manual skims over.

As far as the console removal goes, I just replaced my heater core and rebuilt the box and plenum with new seals and defroster tubes. I found it much easier with the console out and I don’t have AC. I imagine it would be much harder to do on an AC car without removing the console.

I have the center console out and the right side of the heater core box will move back, but it is stuck to the center box assembly, the one behind the radio. I can not get this to release. I do not want to brake anything

There is a nut on the fire wall in about the center right above the transmission tunnel . For reference the nut is just right of where the two boxes come together but under the hood.

Sent you some stuff from the assembly manual. Check your PM folder.

Is the nut next to the inlet of the heater core, on the firewall in the engine compartment. If so there were two nuts that i removed, and I can see the studs, they have not moved. I can get the stud to come out near the passenger side fender, and can see the heater core tubes move in, but I do not see any movement in the studs to the right of the heater core, towards the center of the car.

Did you remove the one bolt that is under the dash? It is near the right side kick panel and goes straight up by where the heater box mates up with the air inlet from the cowl. Also be sure that you have the drain hose disconnected before trying to move the box. If you leave that hose in place and move the box you run the risk of breaking the hose nipple off. You will also need to disconnect the cable and the vacuum lines. I have found it easier to remove the complete box in one piece rather than trying to get the blower motor housing to disconnect from the main box while still under the dash.

Randy Goodling
CCOA #95

I did get that bolt, but did not disconnect the blower motor, is the moto behind the console( I took the console and radio our),
I acan move the box in from the kick panel side, but not where it meets in the center( opposite side)
There are two nuts I took off in the firewall( to the right of the heater core inlet, in line with the left side of the transmission)
When I move the heater box, I do not see these studs move into the car, not sure if they are stuck, or holding something else

You need to remove more than 2 nuts on the firewall side. I would remove the blower motor housing with the heater core box all at one time. It is much easier that way.

Randy Goodling
CCOA #95

We have a 67-8 heater core replacement video coming out in a day or two.

Thanks Don, I will look for the video, I just order the parts from you,

If I remember right, the blower housing is held to the car with one stud through the firewall, and one bolt through an L-bracket to the under-dash / cowl. If you get it loose, you should be able to shift the blower housing over to the driver’s side enough to get the heater box out.
You may also want to remove the little vacuum pod on the upper right side of the heater box to give yourself a little more wiggle room.

Anyway I’m the guy working on the video Don mentioned, hoping to have it done sometime this week. It’s going to be about an hour long, but it does touch on things like removing and reinstalling the console and other bits.

I got the box out,
I had all the nuts out, but had to remove the center lower middle duct. It was a tight fit, I will remove the kick panel on the passenger side to see if it gives me any additional room.

There is some surface rust around the air intake, on the passenger side . Is there any service I should do do before installing the heater box.

Looking forward to this video, I picked up my car with the interior stripped out already and Im working on the process of reassembly. I have all the service and assembly manuals but actually seeing how it comes out and goes back in is a huge help. I cant say I have ever had one of these torn apart before so Im kinda going into it blind since I was not the guy to take it apart. I have had plenty of modern vehicles dashes and plenums out before but that is a different league all together

I am in the process of rebuilding the heater core and I had bought one not knowing the big difference in quality in the different heater cores. WCCC heater core is worth it.

Does anyone know how to test the evaporator, and vacuum valves

You can use a mityvac to test the vacuum actuators