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    Heater Control Valve Sticking

    Hello all. Haven't been here in a while. 2004 Lincoln Town Car, 4.6L. I have a problem with my heater. The heat doesn't (always) get hot even after the temp indicator is in the fully warmed up indication (middle of the gage or a little bit higher). Most time's, after driving a while it'll eventually turn on and get hot. The fan comes on after the temp comes up, so I believe the temp control is working, but it blows cold air...until it decides to blow hot air. I think there is a Heater Control Valve controlling coolant flow into the heater core, but I can't locate it. Can you guys point me in the right direction? Where is this valve, and how difficult it is to replace? If I'm on the wrong track, I'm all ears!

    Sent from my Moto G (4) using Tapatalk

    #2
    There shouldn't be a flow control valve. If anything, there may be a problem with the blend door not moving all the way or the heater core just not getting good flow (may need a good flush). Check the temperature of the heater hoses to make sure both are getting hot. Check after the car has warmed up but you're still getting cool air. If both hoses are hot, then the core should be fine. If one is hot and one is warm or even cool still, then the core is clogged and needs to be flushed.

    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.

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      #3
      Will a faulty blend door give the symptoms I've described? I know the heater core isn't restricted because when it works, it comes on 100% in a moment, like a valve finally opened.

      Sent from my Moto G (4) using Tapatalk

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        #4
        Possibly. If you have the electronic automatic temperature control, it could be an issue with the control head, but I have no clue about those. Others may have ideas about that though. If it's the regular controls, then the blend door actuator may have broken and the door may be flopping.

        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


          #5
          It's not flopping for sure. When it decides to work, it works. I think it's sticking. Just realized I can diagnose the blend door sticking theory easily because I have dual climate control, ie. two blend doors. I have always kept it on the single control setting. I'll put it on dual and see if one side works and the other side doesn't. I'll report back when I've tried it.

          Sent from my Moto G (4) using Tapatalk

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            #6
            Then you probably have the electronic controls. There's a way to run self diagnostics, but I have no clue how. It's been posted on the forums several times though.

            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


              #7
              I went for a ride. The car was still warm from last time I was out. The heat worked from the get go. I put it into dual climate control mode, and raised/lowered the temps of each side. They worked properly/independently. Pretty sure that rules out the blend valves. Then, after the heat was fully up to temp, the heat turned to cold. When I got home, I noticed my temp gage was much hotter than it normally is. I'm going to be embarrassed if it's low on coolant. I'll check the level in the morning after it cools off.

              Sent from my Moto G (4) using Tapatalk

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                #8
                Good news is I'm low on coolant. Bad news is I'm an idiot[emoji1787]. Should have checked that first. I had a ½ gallon of 50/50 and it took all that. Need to buy some more. The leak has got to be small, or only happens underway because I never see a puddle under the car. I do see greenish wetness near the water pump.

                Sent from my Moto G (4) using Tapatalk

                Comment


                  #9
                  Originally posted by sly View Post
                  Then you probably have the electronic controls. There's a way to run self diagnostics, but I have no clue how. It's been posted on the forums several times though.
                  FYI,
                  I did run the self diagnosis. No error codes. Here's the procedure:
                  1. Turn key to engine on position (don't start car)
                  2. Press "off" on the climate control panel.
                  3. Simultaneously press "off" and icon for "directing air to the floor", and then let go.
                  4. Press "auto".
                  5. When completed, it will display either an error code(s), or full panel illumination (all 8's +), indicating no errors.
                  When the self diagnosis runs, it acutates doors and solenoids during the check, so you can hear things happening. It takes 30-40 seconds. Mine displayed the entire display in all 8's +, indicating no errors.

                  Sent from my Moto G (4) using Tapatalk

                  Comment


                    #10
                    Right... I did think of checking the fluid level, but didn't type that out. Now for the fun part of finding the leak. Last time I had this happen to me it was a radiator tank crack at the upper hose. Only leaked when under pressure and not a whole lot either.

                    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
                      I spent several hours trying to find the leak. No luck so far. I'm thinking it may be the intake manifold gasket. I cleaned off a suspect (wet & cruddy) area beneath the thermostat housing and took it for a good ride. When I checked it, it was dry. I pulled the alternator to look behind it, still no smoking gun, but lots of white crusty build up all over. Radiator was replaced last year 'cause I suspected it was leaking, but I now think the leak still exists. Oh well, at least adding coolant is simple.
                      Photos are the top of the head/intake showing a bunch of white crusty crud. What do you think this (white crud) is from?

                      Sent from my Moto G (4) using Tapatalk

                      Comment


                        #12
                        I have found that a pressure tester is a handy tool for finding coolant leaks
                        ..

                        Comment


                          #13
                          can you see down into the valley under the intake? There is a hose in there that can go and you won't see it until it fills the valley up with coolant and dumps out the back. Not familiar with the big plastic thing in yours, but I don't mess with the 4.6 cars much.
                          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

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                            #14
                            04 has the PI engine so it should have the pipe with o-rings instead of the pipe with the short hose on it. Though the o-rings can go bad eventually, but there's 2 or 3 to go bad.

                            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


                              #15
                              That hose went away by '98, but the coolant tube remained. From what I've gathered, the earlier 4.6 had a hose between the nipple/barb and the tube while the later 4.6 has the tube directly connected to the nipple/barb. I'm not sure if the later tube is prone to leaks (anything is with age I suppose), but still worth checking. (Edit: what Sly said.)

                              Not sure if the white crud is concerning.
                              Also not sure of additional spots to check for leaks other than all hoses.
                              On a 5.0 I once had a pinhole in a hose and the leak was not obvious at idle, but as soon as I goosed the throttle I saw the stream shoot out. Could be worth a shot to see if a leak becomes obvious when the throttle is opened up.
                              Vic

                              ~ 1989 MGM LS Colony Park - Large Marge
                              ~ 1998 MGM LS - new DD
                              ~ 1991 MGM LS "The Scab"
                              ~ 1991 MGM GS "The Ice Car"

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