2001 LS V8 Overheating

Lincoln LS

  1. Scottman

    Scottman Active LVC Member

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    Okay, got another mystery. Previously replaced all plastic cooling system parts and installed the aluminum thermostat housing. All was well. The other day I got the check engine temperature message which was backed up by steam from under the hood. Pulled over and had towed home. Okay, no problem bad hose or something. Checked out today. Coolant residual in area of thermostat but started and filled but no leak. Let heat up...no leak. Filled with coolant and bled system. Temperature still exceeding normal. Have been having issue with temperature control last few weeks. In Arizona so run AC all summer. Whenever the temperature spread (inside setting versus outside) is less than 15 degrees or so the passenger side starts blowing warm. So I bump the temperature up to 90 until the left side gets hot and then back down to 65 and passenger gets cool again. That is not working now.
    The gasket in the thermostat housing seemed a little off so tweaked and reinstalled thought that may have been source of leak. So now it is not overheating or leaking but passenger side is always hot. I know for a fact that it was leaking so why not now...I didn't touch anything when I started and no leak? I heard Joeger say the dccv cannot cause overheating without a leak so what is going on here?!
     
  2. joegr

    joegr Dedicated LVC Member

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    You found coolant on top of the engine. There is or was a leak somewhere there. You need to find and resolve that. You need to bleed all the air out.
    I have had thermostats (not the LS) fail on me after an overheat, so I would replace that now as a just-in-case.
    This may have been the last insult for your DCCV, and it may need replacement now too.
     
  3. Scottman

    Scottman Active LVC Member

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    Well I must admit this car is confounding me on a regular basis. In the past when I had a leak it was still there when I went to to address it! I bled the air out after filling. The gasket doesn't look quite right on the thermostat housing (fill port) so I will replace that. No evidence of any wet hoses but you can see spray residual on Top of the hoses coming out of the t-stat housing which made me think the cap was the source. Any tips on replacing the DCCV? Looks hard to get at. I am presuming that is the likely cause of the temperature unordered differential.
     
  4. joegr

    joegr Dedicated LVC Member

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    I do feel your pain in both cases. I don't have a 1st gen, so I have no good advice on getting to the DCCV.
     
  5. Scottman

    Scottman Active LVC Member

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    I appreciate that!
     
  6. AmsterDutch

    AmsterDutch Dedicated LVC Member

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    Cooling System 3.9L - 1st GEN Lincoln LS w/ PN's


    IMPORTANT --> Dccv?
    This will get you pointed in the right direction ...make sure you strech your legs and back before you replace this part...if you don't have a clue what I'm talking about ...you'll know what I'm talking about soon...best of luck!
     
  7. Scottman

    Scottman Active LVC Member

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    Thanks Dutch!
     
  8. FDR

    FDR Dedicated LVC Member

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    I'm assuming the gasket you have is the same o-ring I have. It doesn't like sealing since it fits loose between a flat surface and a tube end. The OEM gasket is a flat washer type. Manoli went back to OEM because it stopped sealing. I've used some caution the couple times I've opened the fill cap and it's been ok for me. I've looked for a suitable replacement washer, but haven't found something rated for the temperature and coolant contact

    Assuming the aluminum cap is an identical copy of the OEM plastic one, the OD is 1.46-1.54", ID is 0.965-1.110", and not sure about OEM thickness. I measured the cap only because I lost the original gasket at some point. There's a few plastic caps on ebay for <$15 that may be worth buying under the assumption they fit the aluminum housing the same
     
  9. Scottman

    Scottman Active LVC Member

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    Ya, pretty much isolated the gasket as the only possible source of the leak. I had the cap off a couple of weeks ago and was not aware of the issue but it didn't seem quite right. This time I installed it with a little more caution so we'll see what happens!
     
  10. AmsterDutch

    AmsterDutch Dedicated LVC Member

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    I used the black OEM plastic Cap on my last 2001 aluminum jag T-Stat housing and it worked perfect
     
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    • 04_Sport_LS

      04_Sport_LS Dedicated LVC Member

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      Scott,

      You probably had, (and may still have), an air pocket in the cooling system. It probably created the original temp spike... which caused enough pressure to bypass the gasket on the cap.

      Since you say it is still running hot... I suggest you bleed the cooling system again.
       
    • Scottman

      Scottman Active LVC Member

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      Ya, bled the system and it seems fine now. Thought I bled it thoroughly last time.
       
    • Scottman

      Scottman Active LVC Member

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      Well, turned out that it wasn't the thermostat housing cap but the upper heater tube, the one I replaced (OEM from Tasca) that is leaking. It is coming out the front of the tube where it connects to the block on the passenger side. Replaced this in late December last year. Doesn't start leaking until the temperature is at 75%. My question is why is it getting to 75% in the first place?
       
    • FDR

      FDR Dedicated LVC Member

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      Loss of pressure can allow local boiled vapor pockets in the head and drastically reduce cooling effectiveness in that spot. Leak = pressure loss. It can also allow air into the system that can collect in high points - maybe inside the head reducing cooling effectiveness, maybe in the thermostat housing and upper pipes and blocking coolant flow
       
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      • Scottman

        Scottman Active LVC Member

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        Thanks for the reply. I will I replace the Upper Heater Tube (again) and see if that doesn't solve the problem. I also ordered a new cap (OEM) for the thermostat housing since I don't like the look of the gasket.
         
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        • AmsterDutch

          AmsterDutch Dedicated LVC Member

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          That OEM Black plastic cap should work fine...are you using Motorcraft thermostat? If not now is a good time to change it out...
           
        • Scottman

          Scottman Active LVC Member

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          Yes, I installed the OEM thermostat with the housing and other plastic parts, but it is never a good time to change that out! Picking up the new heater tube tomorrow morning, along with the $17 hose (I think it is about 3") that connects the tube to the housing and hopefully that solves the problem! Thanks for the reply.
           
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          • 04_Sport_LS

            04_Sport_LS Dedicated LVC Member

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            Short answer:

            As the cooling system heats up... it builds pressure. The pin hole/crack might not be bad enough to leak at 5psi ... but as system reaches 10psi ... it may.

            Keep in mind that the system is rated at 16psi.
             
          • Scottman

            Scottman Active LVC Member

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            I replaced the heater tube today and changed the thermostat housing cap to the OEM. So hopefully we'll be good! The heater tube was new in December!
             
          • AmsterDutch

            AmsterDutch Dedicated LVC Member

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            You should be good ...knocking on wood lol ...We all are at the mercy of the parts manufacturers...and it's a fact of life that some parts will be defective and still be shipped out to customers ...best case scenario is just that a defective part was shipped to you ...other wise there is something else going on with your LS ...keep us posted Scott
             
          • Scottman

            Scottman Active LVC Member

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            Will do!
             
          • Scottman

            Scottman Active LVC Member

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            Well ran fine to work (17 miles) and then the needle started moving. Worked my shift and then bled the air again..a little came out. Ran fine most of the way home and about 2 miles shy of home needle started rising. Pulled over and inspected. No leak.. coolant level at minimum but hot! High pressure on both hoses and the coolant coming out of the bleed hose was sizzling. Can't be a stuck thermostat right! When I bled it earlier it came out normally so there was flow. I am baffled. Sitting at a gas station 1 mile from home waiting for it to cool down enough to get there.
             
          • Scottman

            Scottman Active LVC Member

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            Okay, let it cool, cranked the heater and made it home fine. Let run in driveway (with heater on) and temperature remained stable. No leaks and coolant level good. Any ideas?
             
          • joegr

            joegr Dedicated LVC Member

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            The 1st gen thermostat is a pretty cheap thing to throw at it as a just-in-case...
             
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            • Scottman

              Scottman Active LVC Member

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              Yep, will do that first.
               

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