'82 Mark VI heater core replacement, dew wipes, & window channels/seals

[sxcpotatoes]

Hey, the heat has never worked in the Mark VI I bought from Sly (except for perhaps on the drive home and one time under heavy load/acceleration it came on briefly), and I'm on vacation next week and was thinking about pulling the dash and getting everything in there replaced. My mechanic pointed out a thing that they used to zip tie to get heat in the winter, there's some valve or something up at the top of the motor I will have to get pictures of, but when I tried to do that it never put out any heat. The A/C cuts way down at anything over 1/3 throttle too so I'm sure I have vacuum leaks I need to take care of. The A/C comes out everywhere. I was planning on doing the heater core, blend door, diverter, blower motor, and wheel, if I can get all the parts, etc.

Another problem is I can't get in the glovebox. Those pot-metal latches kinda broke, and no matter how hard you squeeze it won't release, and I was wondering if there was any trick to popping it without breaking anything, etc. Especially if there are bolts I have to pull to yank the dash behind there.

I may finally tackle the dew wipes and window channel as well, if I have time, but I'm missing at least 1 clip for up in the window channel, are those explicitly needed?

I will try to get some pictures of it all this afternoon after I get home from work. Also any suggestions for heater core/blend door parts brands or anything would be helpful. I know to seal off the heater core and dunk it to check for leaks before installing, and about the 3/8 socket to put in for flow restriction (anybody remember what diameter?). I had the mechanic I had fix my A/C in the '91 do the heater core at the same time (he had to grind down a 3/8" 3/8 socket to get it to fit for flow restriction), but he fucked up the diverter or plenum or something and now on Defrost, the air whistles out the damn vents as well. For now we've been closing the vents to try to use Defrost on that. So this will be a good practice run for getting in there and fixing the '91 properly even though there are some slight differences.

Thanks.

Also I have to do the passenger side window motor on the '82 to even be able to get to the window channel/dew wipes because it quit awhile back.

[Tiggie]

When you say the A/C cuts out above 1/3 throttle - do you mean the vent temp starts warming up (kind of like the heat tries to come on)? If so, that’s a good sign that things aren’t too screwed up in the HVAC box. It certainly has a vacuum leak or three somewhere. Start at the coffee can and verify that holds vacuum. Trace back to the “vacuum distribution block” on the firewall. You should find a check valve between that and the engine vacuum source - check that as well. Then it’s a big party of searching for more leaks.

I am guessing this is ATC.

Glove box should have screws at the hinge on the bottom that should allow you get to the latch mechanism from the bottom. Could use a pic once you get it open to see what has been screwed around with in there.

On the socket, you want one with a diameter that is just slightly larger than the heater core inlet/outlet.

My 88 was a combination of a bad coffee can, check valve, and temp sensor. It had cool air all the time except under heavy acceleration or extended high load.

[sly]

Sounds like the check valve died again. Motorcraft YG337.

The air plenum probably needs to be resealed. All the foam seals are probably dead and gone which is why it blows out everywhere and never really to the place you want it.

If you do go through all of that, you may want to remove the heater hose diverter I put on the thing if you haven't already. I totally dreaded pulling that dash to replace the heater core. It's probably got all manner of crap clogging it up as well.

[sxcpotatoes]

The A/C dies like the blower motor cuts out (might be WOT cutout triggering, it is still running rich since last year's Scottfest). I will get pics shortly. If it's just the check valve is that up in behind the glove box? If that's all it needs and gets me heat I'm okay with closing the vents and heat coming out everywhere. I've got a ton of stuff to do around the house to get ready for winter, and the car comes last for now, sadly.

[gadget73]

To get heat, pull the clear vacuum line off the thing directly behind the glove box. If that makes it work, the interior sensor is shot. Thats the thing above the glovebox.

If it shifts on accel, its a vacuum leak or a check valve problem. Check valve is on the firewall, basically center behind the upper intake. It plugs into the vacuum tree and has two lines coming out of it, one to the soup can and one that loops into the dash. Verify the valve works, the line to the soup can is good, and the can itself holds vacuum. If no soup can, make sure whatever vacuum can is there is holding. Also make sure the thermal blower lockout is good, or properly sealed off if it has been removed. All of that is on the main vac feed so problems there really screw it up. If the engine bay bits are good, you may have a leak inside the climate control selector or someplace in the dash. Its an old car that uses little rubber bits to seal stuff, things fail. I do not believe that selector mechanism is rebuildable, though you can remove the actual vacuum valve from the unit to swap with another so you can keep the original cosmetic appearance.

If the fan is on auto, the fan speed will slow as the blend door swings towards the middle. The WOT cutout only turns off the compressor, it does not affect the fan. It also will not have any effect if you have it on one of the manual speeds. The air will shift to defrost though, which might be what you're noticing.


On the subject of that sensor, I took one apart and be damned if i can see what actually fails in there. Its a spring with a little needle that moves in and out. Best guess is that it gets dirt in there and stops sealing. Possible that washing the thing out will fix it. Maybe a dunk in an ultrasonic cleaner is the magic fix. Taking them apart pretty much destroys them unfortunately.

[sxcpotatoes]

First is how chunky the window seal is getting, second is a clip that's holding the window seal in, with the new seal, can/should I eliminate these clips? I thought there were one or two more on the front side somewhere in the window channel, or that I was missing one, I don't know.

Last is the thing my mechanic pointed out to me that needed to be zip tied to get heat, I tried it but it didn't put out any. I guess back in the day, it was a common problem for a Lincoln to lose heat and the fix was to zip tie that arm vacuum actuated thingy up by the intake and you'd have heat.

[gadget73]

Never seen clips like that, not sure if original or added in.


Sly will have to explain the thing under the hood. Its something he added to boost AC performance. If the vacuum system works properly, that shouldn't be your issue. It wouldn't have been common to do anything to that part years ago because none of these cars ever had one from the factory.

[VicCrownVic]

CV/MGM without vent windows also have those clips, but not in that location. I have no idea if they actually serve a purpose though.

+1 the heater core cutout is not stock, as far as I know. No idea if that one is normally open or normally closed and which you would want to replace it with.
+1 Sly can probably tell you which way that thing needs to be zipped tied to keep it open. Also, assuming the vacuum line to that valve is working properly.
Normally closed, but I think the inlet/outlet is the wrong size: https://www.ebay.com/itm/NEW-FORD-ST...-/401269495790


The other fix is grab a hose barb union from the hardware store and put it in place of the cutout valve.
https://www.ebay.com/itm/3-4-Hose-Ba...frcectupt=true

If the cutout valve is not desired order a hose for a non-ATC car like DAYCO 88433 which replaces both hoses on either side of the cutout valve.

[sxcpotatoes]

Thanks for the suggestions, I ordered a check valve for now (I have the dew wipes and window seals here). My dad said those clips are important and help guide the window glass up into the channel so they don't fuck up/pinch the window channels, so I will have to wire brush and paint those when removed. Today it's supposed to be 60! So I will possibly attempt to do the driver window seal and wash the car. Will have to read up on it here http://www.grandmarq.net/vb/showthre...tripping/page5

[sxcpotatoes]

Jeez, did you know the window channel seal goes all the way down to the bottom of the door? Short of removing the glass, or doing it with the window up, then down, not happening today. I got the main part all the way around and down as far as I could on each side. Tight AF on the front window trim seal. Pics coming tomorrow if I have time. A lot quieter on the test drive. Don't have time to check for leaks today.

[sly]

Vacuum is pulled from the panel vents for that actuator and that will CUT OFF coolant flow to the heater core. You can actually just remove that whole rig and remove the T behind the ash tray on the panel vent actuator and put the original connection back to the actuator. (Blue line IIRC.) By default it allows flow to the heater core. So yeah... it's clogged again.

The blower cutting out is probably what was already mentioned about the dash sensor. Also, the white hose that goes to the firewall that gets the air flowing over said sensor was glued in place with RTV and may have fallen off. The nipple that is supposed to be there does not exist. I bought the car that way. You may need to re-attache that hose.

[87gtVIC]

Jeez, did you know the window channel seal goes all the way down to the bottom of the door?

I knew. Not a quick job by any means.

[gadget73]

yeah, its annoying. Have to remove the door panels and basically work the glass up and down to get the channel out. Removing the petrified old shit takes more effort than installing the new. That you can lightly lube with some silicone spray and slide it into place without much effort.