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2007 Lincoln Town Car - AC warmer when moving, Cooler when idling

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  • 2007 Lincoln Town Car - AC warmer when moving, Cooler when idling

    Hi there, I have a 2007 Lincoln Town Car 4.6L.

    On a hotter day like today, 84 degrees, 51% humidity when my car is moving at 35 mph the vent temps are 55-60. If I let the car idle for 5 minutes they go down to 38-40. This is with recirc on, fan medium.

    I did some testing with the following results.
    Temp set for lowest setting, fan on high, recirc off, windows open.

    At idle, compressor runs continuously low side 30-35, high side 220-225.

    At 1500 rpm compressor cycles (every 5 seconds??), low side 15-60, high side 150-225.

    Rad fan runs continuously at idle don't know what it does when rev's are up. Will need a helper to watch for that.

    I'm only guessing how often the compressor cycles as I'm by myself and can't operate the throttle and see the compressor or fan.

    Any help would be appreciated, thanks!

  • #2
    Fast cycling and low, low side when the compressor is on at speed suggest the charge is low (with a CCOT system). Not real low, but still not right. Only way to be sure of charge is to evacuate and charge by weight.
    If it low, it must have leaked so first order of business is to locate and fix the leak.

    Comment


    • #3
      You saw a low pressure of just 15? It would cycle at that. At just idle you actually don't need or available the load or need for the BTU power of system like at speed low charge would be exhausted quicker reading way to low - no compressor and the warmer air.

      Same as Cornbinder said I'll add super high chance just low from a leak. If you know this car for ages has it slowly done that? Just asking if sudden or if a fast leak.

      You can look for oily evidence condenser even bugs small debris damage and oily, connections and no so likely find the drip hose or hole and see if it's oils you don't want that = evaporator likely.

      Other stuff? Just because check that the air dam under bumper is intact - it could bust off and at speed the air flow jams under the car where exiting heat needs a slight vacuum just normal shape of things if all wrong can't expel heat fast enough. Doubt that one, check anyway. Low charge most likely - look or get it checked and sooner the better it's cooling at all is good so don't wait,

      (edit out at least one typo !)


      Tom
      MetroWest, Boston

      Comment


      • #4
        Originally posted by Cornbinder89 View Post
        Fast cycling and low, low side when the compressor is on at speed suggest the charge is low (with a CCOT system). Not real low, but still not right. Only way to be sure of charge is to evacuate and charge by weight.
        If it low, it must have leaked so first order of business is to locate and fix the leak.
        My AC guy is away for awhile so I'll add some and see what happens.
        Thanks for the help. I wasn't sure if it was low or not.

        Comment


        • #5
          Originally posted by Tom Greenleaf View Post
          You saw a low pressure of just 15? It would cycle at that. At just idle you actually don't need or available the load or need for the BTU power of system like at speed low charge would be exhausted quicker reading way to low - no compressor and the warmer air.

          Same as Cornbinder said I'll add super high chance just low from a leak. If you know this car for ages has it slowly done that? Just asking if sudden or if a fast leak.

          You can look for oily evidence condenser even bugs small debris damage and oily, connections and no so likely find the drip hose or hole and see if it's oils you don't want that = evaporator likely.

          Other stuff? Just because check that the air dam under bumper is intact - it could bust off and at speed the air flow jams under the car where exiting heat needs a slight vacuum just normal shape of things if all wrong can't expel heat fast enough. Doubt that one, check anyway. Low charge most likely - look or get it checked and sooner the better it's cooling at all is good so don't wait,

          (edit out at least one typo !)

          I added some and at 80 degrees, 51 % humidity at idle low is 48 high is 250.
          At 1500 rpm low is 30 high is 320. The gauges held steady so it doesn't seem to be cycling like before.

          I just got the car last fall. It may have a slow leak somewhere, not sure yet.
          Does have dye in the system. Can't see any anywhere other than the charge port when I put the gauges on.
          The previous owner did have a dealer install a new rad, condenser and accumulator 2 years ago.
          No damage anywhere I can see and good air flow.

          It's supposed to get warmer later this week.

          Thank you Tom and Cornbinder for the help!

          Comment


          • #6
            320 @ 1500 and 80 deg is too high, possible you added too much or have poor airflow over the condenser. It shows why "topping up" without knowing how much is in the system is a crap shoot at best and detrimental at worse. You risk burst hoses or a blow off valve (if equipped) opening.

            Comment


            • #7
              Yup - Added too much. It will most likely damage the system now or quit by itself if failsafe are working properly. You saw leaking at a port and dye in it. That's so far normal just hooking up there's a spit of loss would show. Best now is disable it NOW before damage just maybe there's not any yet but will be.
              Odd that your A/C person is away could be a legitimate reason but it's prime time for work so find another.

              I mean it - DISABLE IT IF AND POSSIBLE TAKE THE PLUG OFF THE COMPRESSOR, TIE IT AWAY SO IT CAN'T WORK BUT WITH HEAT RATED WIRE TIES OR SOMETHING OUT OF THE WAY OF MOVING PARTS, HOT PARTS AND WHERE IT CAN'T SHORT OUT.

              Bad move to just aimlessly blast refrigerant into anything that uses it unknown how catastrophic you just made this!
              ,
              Tom
              MetroWest, Boston

              Comment


              • #8
                Ok guys, I'll remove the compressor plug. It's easy to get too.
                My AC guy runs a small auto repair shop and he shuts down to give himself and employees a summer vacation.

                Thanks again for the help!

                I did figure out how to use Forscan to tell me if the compressor is on and also the high pressure while I'm in the vehicle so that was good.
                Last edited by tcclav; 07-17-2019, 10:50 AM.

                Comment


                • #9
                  You know it was compressing if you saw 320 PSI. Pull plug or if a dedicated A/C fuse. Protect the plug. PROBEM might (said might) be fan(s) whatever this uses with whatever options may not totally work? So watch temp gauge for engine like a hawk too despite automatic warnings.

                  Almost any "engine" will really hate getting warm to really hot and boil inside. What stinks is the dang sensors, many are then in vapor go brain dead as the jerk that designed them (clearly I'm not fan of some engineering junk out there in almost anything) then this problem can and will harm engine and more.

                  Not my job nor technically legal or safe is to let some gas out. Can't say that as if refrigerant decides to go all at once right at you, hands, eyes!! or whatever it's flash unreal cold is no better than a powerful flame burn to YOU.

                  Good luck just of all things don't get hurt and really think about any possible savings vs learning an awful lot if only to not wreck things just trust me/us and quoting I believe a late member of these forums "ACPROF" would say "The tuition for learning by mistakes is very costly" or close to that.

                  I'm not looking up where you are just use common sense if you drive this without A/C for a little while even here where I am will be well over 100F isn't safe anymore especially stuck in traffic too common where I am,

                  Tom
                  MetroWest, Boston

                  Comment


                  • #10
                    Ok, I'm going to follow your guys good advice and also tackle this myself.
                    Ordered a vacuum pump that should be here tomorrow.

                    Engine temps are always at 188-190, rad fan works great, cowling is good and both condenser and rad are clean.
                    Sticker calls for 23oz of R134a. I have a scale that I will use but I'm thinking that after I purge the lines two 12oz cans should be pretty close.

                    Comment


                    • #11
                      Lucked out cans vs capacity: Just make SURE you are fully in well held vacuum. If at all possible you can use cans thru gauges and while hooked up in full vacuum spit air out of can/hose rig you have or create and put some in high side can watch it go OUT of vacuum on low side. Now you are good to go with two cans is IMO close enough some lost just your gauges, hook ups would be spot on.

                      Side note question: ?? What are you reading for seeing engine OPERATING temp of 188 - 190F ? That's really not hot enough not going to look up T-Stat required rating but if that's accurate to you and sure it's too low.

                      Almost all with either electric fan or electric clutch belt driven should stay exact but higher at thermostat outlet right at it by a tad more. No fluctuating unless fan(s) or combo set up is funky somehow.

                      I can't know Town Cars you always could opt for wild cooling (engine) meaning for Limousines or some Livery cars, some sold for rentals used to be marked at such or in code up to plain say so on tiny stickers could find them.

                      It's all OK just the engine itself needs to be and is at those "engine" temps in "closed loop" meaning it's ready to let a dang computer run the whole show if too cold around 180 +/- isn't yet and matters.

                      Anyway - just know if you are pretty sure of correct charge and see spikes in high side again it isn't right. That would blow warmer again with more engine RPM compressor can do more.

                      Sorry for long reply I know most of the country is quite hot or has been but these cars historically run powerful A/C if not let's find out why.

                      One more: weigh both cans first see if the same. Then weight the empty by brand as you are using it with or without a tap of choice find the "tare" weight. Had troubles with some not the same and it's not my scales (use two or more to verify that. Just FYI on that,
                      Tom
                      MetroWest, Boston

                      Comment


                      • #12
                        With purging of the lines, loss on removal of fitting, some remaining in cans, will be tough to get 23 oz. from two 12-oz cans. I'm thinkin' "maybe" but 2.5 cans seems better. I'd also add some UV dye, or can use oil that contains UV dye already, or believe there is R134a that contains UV dye.

                        NEVER ADD ANY SEALER OR REFRIGERANT CONTAINING SEALER !!!

                        Comment


                        • #13
                          Originally posted by Tom Greenleaf View Post
                          Lucked out cans vs capacity: Just make SURE you are fully in well held vacuum. If at all possible you can use cans thru gauges and while hooked up in full vacuum spit air out of can/hose rig you have or create and put some in high side can watch it go OUT of vacuum on low side. Now you are good to go with two cans is IMO close enough some lost just your gauges, hook ups would be spot on.

                          Side note question: ?? What are you reading for seeing engine OPERATING temp of 188 - 190F ? That's really not hot enough not going to look up T-Stat required rating but if that's accurate to you and sure it's too low.

                          Almost all with either electric fan or electric clutch belt driven should stay exact but higher at thermostat outlet right at it by a tad more. No fluctuating unless fan(s) or combo set up is funky somehow.

                          I can't know Town Cars you always could opt for wild cooling (engine) meaning for Limousines or some Livery cars, some sold for rentals used to be marked at such or in code up to plain say so on tiny stickers could find them.

                          It's all OK just the engine itself needs to be and is at those "engine" temps in "closed loop" meaning it's ready to let a dang computer run the whole show if too cold around 180 +/- isn't yet and matters.

                          Anyway - just know if you are pretty sure of correct charge and see spikes in high side again it isn't right. That would blow warmer again with more engine RPM compressor can do more.

                          Sorry for long reply I know most of the country is quite hot or has been but these cars historically run powerful A/C if not let's find out why.

                          One more: weigh both cans first see if the same. Then weight the empty by brand as you are using it with or without a tap of choice find the "tare" weight. Had troubles with some not the same and it's not my scales (use two or more to verify that. Just FYI on that,
                          Sorry, I'm not familiar with the terminology and procedures so I don't understand when you say.
                          "Lucked out cans vs capacity:(I get the cans versus capacity part) But not this part Just make SURE you are fully in well held vacuum. If at all possible you can use cans thru gauges and while hooked up in full vacuum spit air out of can/hose rig you have or create and put some in high side can watch it go OUT of vacuum on low side. Now you are good to go with two cans is IMO close enough some lost just your gauges, hook ups would be spot on."

                          As far as the engine temps go I'm getting it from both my Torque App and my Forscan App. They're getting it from the ECT-OBDII coolant sensor.
                          You have a good point that's it's a bit low. The thermostat was supposedly replaced with a Motorcraft 195 a few years ago. I'll pull it out and check it though.
                          I'll also check the thermostat housing with my IR gun.
                          I did check vent temps this past winter and they were 150 degrees when it was -20 C out.

                          I have already weighed both the cans and the 3 can taps I have. The cans did vary by a 1/2 ounce or so.
                          Good idea about weighing them after.

                          Thanks!


                          Comment


                          • #14
                            Originally posted by Cusser View Post
                            With purging of the lines, loss on removal of fitting, some remaining in cans, will be tough to get 23 oz. from two 12-oz cans. I'm thinkin' "maybe" but 2.5 cans seems better. I'd also add some UV dye, or can use oil that contains UV dye already, or believe there is R134a that contains UV dye.

                            NEVER ADD ANY SEALER OR REFRIGERANT CONTAINING SEALER !!!
                            I was hoping if I put the cans in hot water I might have a chance of getting close to 23 oz??.
                            I just didn't want to over charge it again.

                            It does have UV dye in it right now. Will that be gone after I vacuum it?
                            I wasn't going to ad oil, should I be?

                            After I hold the vacuum for 30-60 minutes do I have to purge the high and low hoses or just the yellow feed hose after putting the can on?

                            Won't be adding sealer!
                            Appreciate the help!

                            Comment


                            • #15
                              Notes: Well held vacuum? It holds if it creeps back up try again. Make sure all hoses if using a gauge set are tight.
                              Easy on "hot" water. Not so hot that you can't touch it.
                              Get extra cans - weight them all.
                              Dye is not lost.
                              If you don't think you got close to your 23oz and all else is right with the system the accumulator wouldn't be cool/cold with compressor staying engaged. Can take a run around the block (sometimes) for oil to all resettle where it will and work its best. Easy rechecking pressures too much you lose a spit each time this is a low capacity system really wants to be within (guess) 5-10% of the charge listed. Just AVOID way too much if into a third can.

                              Good luck,
                              Tom
                              MetroWest, Boston

                              Comment

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