Announcement

Collapse
No announcement yet.

1985 Ford weak airflow on left side dash registers

Collapse
X
Collapse
 
  • Page of 1
  • Filter
  • Time
  • Show
Clear All
new posts
Previous template Next
    #1

    1985 Ford weak airflow on left side dash registers

    This is re: my wagon.
    AC is working on this car (thankfully, as the weather is good and properly soupy now), but I'm finding I have weaker airflow on the left 2 dash registers vs the right 2.
    Having had the dash and HVAC plenum out to replace the heater core and repair the hinges on the doors, I cannot think of any particular reason why the right side vents would get more airflow.

    Any thoughts, please? Is this just how they are perhaps because of the shape/routing of the ducting?

    Panthers: 83 GM 2dr | 84 TC | 85 CS | 88 TC | 91 GM | 94 CV
    Not Panthers: 85 Ranger | Ranger trailer | 89 Ranger | 91 Acclaim | 92 Jaaag | 05 Focus
    Gone: 97 CV | 83 TC | 04 Focus | 86 GM | Junkyards
    Tags: None
    #2
    how does the air door angle into the chunk of duct that feeds the dash vents? If its slightly angled towards the right side that may be the reason. Otherwise probably just size/shape of the ductwork.
    86 Lincoln Town Car (Galactica).
    5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

    91 Lincoln Mark VII LSC grandpa spec white and cranberry

    1984 Lincoln Continental TurboDiesel - rolls coal

    Originally posted by phayzer5
    I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

    Everything looks like voodoo if you don't understand how it works

    Comment

      #3
      is the foam in the duct joints still there? Could just be leaking half of it behind the dash.

      Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. -- Albert Einstein
      rides: 93 Crown Vic LX (The Red Velvet Cake), 2000 Crown Vic base model (Sandy), 2003 Expedition (the vacation beast)

      Originally posted by gadget73
      ... and it should all work like magic and unicorns and stuff.

      Originally posted by dmccaig
      Overhead, some poor bastards are flying in airplanes.

      Comment

        #4
        Shape-wise, I can't really see why it would vary. I'm looking at a couple pics here for reference. https://www.grandmarq.net/vb/forum/t...13#post1160181

        Any foam that existed, no longer does. So some loss at joints is definitely likely. It's just weird that the right side vents would feel strong but the left side don't. I don't remember exactly how the duct assembly (the part that stays in the dash when you pull it) goes together but I feel like the key to this is in that.

        As I understand it, the 2-piece door controls dash vents. When the selection is vent, AC, or max AC, both pieces of the door will be open, sending 100% of the air to the duct in the dash.
        If the selection is hi-lo, it only opens the small part of the door, allowing the rest to go over to the floor-defrost door, which I think would be in the halfway position e.g. send some air to all openings.

        I'll see if I can scope out what's up inside the dash. Maybe a piece of the duct assembly came disconnected or something.

        Panthers: 83 GM 2dr | 84 TC | 85 CS | 88 TC | 91 GM | 94 CV
        Not Panthers: 85 Ranger | Ranger trailer | 89 Ranger | 91 Acclaim | 92 Jaaag | 05 Focus
        Gone: 97 CV | 83 TC | 04 Focus | 86 GM | Junkyards

        Comment

          #5
          My 89 Colony Park has weak vents on the left side too. I closed the right vents tight and it seems to help a lot. WagonMan
          89 Colony Park
          90 Colony Park
          70 HEMI Daytona Convertible

          Comment

            #6
            If it is any consolation, on mine the center and right side vents blow harder than the left one. Not by much but its noticeable. The floor vent also blows little bit regardless of knob position.
            1985 Mercury Grand Marquis LS, "Maisa"
            2005 Volvo V70 Bi-Fuel

            Comment

              #7
              in the 88 MGM I had, the left vent always was weak. Center was good and right was always the middle. The center is the shortest run, right is next shortest and the left is the longest run with the most segments. That car would always freeze my feet with the leaky ducts behind the cluster before ever cooling my left shoulder.

              Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. -- Albert Einstein
              rides: 93 Crown Vic LX (The Red Velvet Cake), 2000 Crown Vic base model (Sandy), 2003 Expedition (the vacation beast)

              Originally posted by gadget73
              ... and it should all work like magic and unicorns and stuff.

              Originally posted by dmccaig
              Overhead, some poor bastards are flying in airplanes.

              Comment

                #8
                I'm currently working with my own HVAC issues and noticed the gap between the vent ducts and the plenum with all the doors is wide enough to see through, which can't be doing the system any favors.

                The geometry of the ducts must be a big part of why some vents are stronger than others, but I wonder if it wouldn't matter if the airflow was stronger. Has anyone ever swapped in a blower motor from something newer? Maybe it's my imagination, but it sure seems like my '20 Odyssey is moving a lot more air through its vents than the Town Car is.
                1987 Lincoln Town Car - Signature, "Prudence"

                Comment

                  #9
                  I think someone, perhaps sly, had described a relay mod (and perhaps a ground upgrade?) for the blower motor that gets a little more oomph out of it. It makes sense: if you trace the circuit feeding the blower motor, it goes through a lot of opportunities for voltage drop.

                  If there's a gap where the ducts meet the plenum that's 100% a contributor. Guess I need to actually look at my problem like you did, rather than just guessing and leaning on all of you lol.

                  Perhaps they make some sort of tape...perhaps marketed as being for duct-related purposes...

                  Panthers: 83 GM 2dr | 84 TC | 85 CS | 88 TC | 91 GM | 94 CV
                  Not Panthers: 85 Ranger | Ranger trailer | 89 Ranger | 91 Acclaim | 92 Jaaag | 05 Focus
                  Gone: 97 CV | 83 TC | 04 Focus | 86 GM | Junkyards

                  Comment

                    #10
                    yeah... If anyone wants specifics on the blower relay mod, check this thread: https://www.grandmarq.net/vb/forum/t...r-blower-motor

                    Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. -- Albert Einstein
                    rides: 93 Crown Vic LX (The Red Velvet Cake), 2000 Crown Vic base model (Sandy), 2003 Expedition (the vacation beast)

                    Originally posted by gadget73
                    ... and it should all work like magic and unicorns and stuff.

                    Originally posted by dmccaig
                    Overhead, some poor bastards are flying in airplanes.

                    Comment

                      #11
                      Thanks for linking that. Seems to be a common theme for these cars: when in doubt, add a relay.

                      I remember talking with an HVAC guy a couple years ago about how they design the ducts for home central air. He said they will vary the duct size and add baffles to balance the flow to each register. The panel ducts are what they are, but I wonder if you could add some baffle somewhere in there to get more air to the driver's side - assuming everything else is working as expected.
                      1987 Lincoln Town Car - Signature, "Prudence"

                      Comment

                        #12
                        Originally posted by Lutrova View Post
                        Thanks for linking that. Seems to be a common theme for these cars: when in doubt, add a relay.

                        I remember talking with an HVAC guy a couple years ago about how they design the ducts for home central air. He said they will vary the duct size and add baffles to balance the flow to each register. The panel ducts are what they are, but I wonder if you could add some baffle somewhere in there to get more air to the driver's side - assuming everything else is working as expected.
                        I think Wagonman/Pete offered a possibly wonderful solution. Close the others and just leave the driver's side open (assuming you are the only one in the vehicle).
                        What I Own: 1993 Mercury Grand Marquis GS
                        What I Help Maintain: 1996 CV / 1988 CV / 1988 Tempo

                        Comment

                          #13
                          the relay mod also gets a significant current load out of the ignition switch, not the worst thing.
                          86 Lincoln Town Car (Galactica).
                          5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

                          91 Lincoln Mark VII LSC grandpa spec white and cranberry

                          1984 Lincoln Continental TurboDiesel - rolls coal

                          Originally posted by phayzer5
                          I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

                          Everything looks like voodoo if you don't understand how it works

                          Comment

                            #14
                            so having recently had a good look inside the dash at the ductwork, I can say I understand why the air distribution is what it is. If you look in through the center vents, the air feed is on the right side. Its a very large area running down to the top of the plenum assemby with a fairly straight duct over to the passenger side as well. In the middle between those two vents the duct gets a whole lot smaller so less air can go through, and it has to continue on through a not so large duct across behind the speedometer to the driver's side vent

                            so basically the whole thing is pinched from the left-center vent over to the driver's side and there really isn't anything you can do about it. Leaks will make it worse but its never going to be even.

                            also WRT the relay thing. Some poking tonight at mine shows slightly more than 2 volts difference from battery + to the + side of the blower, and about 1v of drop from battery + to the fuse. I think the relay mod is on the short list, that will unload a bunch off the ignition switch and gaining ~2v at the blower should make a nice difference there too. There is still close to 1v of drop on the ground side but not sure there is much I can do there.
                            86 Lincoln Town Car (Galactica).
                            5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

                            91 Lincoln Mark VII LSC grandpa spec white and cranberry

                            1984 Lincoln Continental TurboDiesel - rolls coal

                            Originally posted by phayzer5
                            I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

                            Everything looks like voodoo if you don't understand how it works

                            Comment

                            Previous template Next
                            Working...
                            X