bad thermostat?

Lincoln Mark VIII

  1. 98LSC32V

    98LSC32V Dedicated LVC Member

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    I was driving on the freeway today when I noticed the temp gauge rising fast. As soon as we hit an uphill, it quickly got into the red and I pulled over and popped the hood. After sitting for like 15 minutes, the coolant in the overflow bottle was drained all the way to the bottom. I didn't have any tools with me so I refilled with coolant/water with the engine running and heat all the way on. I made sure there were no pockets left but the car still slowly was creeping up on the temp gauge and I barely made it home. I had to pull over a couple times to let the engine cool down. The fan was definately working and i'm pretty sure there are no air pockets left in the cooling system. Does this sound like a bad thermostat? This was on the 96 Mark VIII, all stock, 66k miles on it.
     
  2. MrWilson

    MrWilson Dedicated LVC Member

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    lol, sounds like me :) same miles and all! The t-stat isnt hard or expensive to replace if you wanna give it a shot. If that doesnt work, try the water pump. after that, i dunno, lol.
     
  3. 98LSC32V

    98LSC32V Dedicated LVC Member

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    I've had a water pump go bad on my 95 and it doesn't show the same symptoms... you can usually see coolant dripping right from underneath the water pump but usually the car can still maintain normal temp... Did you get the Napa 180 degree thermostat Mr. Wilson?
     
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    • NYC LS8

      NYC LS8 Dedicated LVC Member

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      I'd bet on the thermostat. I just went through that last Saturday with my 92 wth the gauge all over the place.
       
    • 98LSC32V

      98LSC32V Dedicated LVC Member

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      Will a Napa 180 degree thermostat for a 96 Cobra work? They didn't have a 180 degree thermostat for the Mark VIII...
       
    • JC1994

      JC1994 Dedicated LVC Member

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      *owned*
       
    • MrWilson

      MrWilson Dedicated LVC Member

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      the only one i could find was a 195deg t-stat. I was looking at the "cobra" ones, which were 180 but they didnt look the same, and i figgured they wouldnt fit.
       
    • 98LSC32V

      98LSC32V Dedicated LVC Member

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      I got the Cobra 180 degree Napa thermostat installed today, no fitment problems. The car doesn't overheat anymore although I need the fan to come on earlier to take full advantage of the 180 degree thermostat.
       
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      • MrWilson

        MrWilson Dedicated LVC Member

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        put it on MAX A/C. That turns on your fan no matter whats goin on.

        The 180...does it look exactly like the mark's? or does it look a little diff.
         
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        • BigredLsc

          BigredLsc Active LVC Member

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          I’m wondering the same thing haven’t same issue with my 97 lsc
           
        • popstar

          popstar LVC Member

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          The mark viii and 96-98 cobra thermostats are identical.
           
        • BigredLsc

          BigredLsc Active LVC Member

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          Are u sure ? So it’s 195 degrees ?
           
        • popstar

          popstar LVC Member

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          Definitely sure because I own both cars.
          This is in reference to the size of the thermostats. You can get them 160, 170, 180, 188, and 195 degrees. Most people recommend 170 or 180. I have a 180 thermostat I bought from rock auto: Stant Superstat 14138 180 degrees.
          You can use any thermostat for a 93-98 mark viii or 96-04 mustang cobra or 03-04 mach 1, they are exactly the same size and will fit into the housing.
           
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          • BigredLsc

            BigredLsc Active LVC Member

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            I see thanks for that info .. but if my car is all stock (except my radiator is aluminum by company called griffin) then I would only be able to run 195 rite ? Without doing a tune for 180 degrees
             
          • popstar

            popstar LVC Member

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            Yes you shouldn’t have a problem. If you live somewhere where it gets very cold then 195 should be ok. But for the south and southwest (I’m in Phoenix) most people run 170 or 180 or lower to keep intake air temps down. These engines run hot so anything you can do to make them run slightly cooler is generally recommended. I would imagine with that nice griffin radiator you won’t have any problems whatsoever.

            Question: did you have to trim your fan shroud and remove your egr pumps in front of the engine to fit the Griffin?
             
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            • BigredLsc

              BigredLsc Active LVC Member

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              No I didn’t have to trim anything the fan and shroud fit perfect along with that Secondary air pump Is still there ! Yea well I’m wondering if I’m having the air bubbles stuck inside issue because I’m in Cali and only on days when it’s 95 plus degrees outside and I have been driving the car for awhile the needle will begin to teeter upwards towards the 3rd Quarter line before It’s hits the hot ! And that’s mainly only when I have the A.c on which comes out ice ice cold ! So everything in my cooling system too is new radiator water pump all the hoses and the system is full 3 days in a row I drove and then check it next morning when it’s cold and my resivor which is also new is full and so is the cross over , The only thing I can think of that I haven’t changed yet at all is the thermostat or if there’s still air inside my system shaking my head
               
            • popstar

              popstar LVC Member

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              The air in the system would only be in the crossover tube I think. That’s the highest point of the system, designed this way to trap air if it’s in the system. The best way to know is to get an ultra gauge (or scangauge) to see real time the exact temperature. I also was chasing overheating issued until I realized that my mark’s temp gauge is just sensitive and likes to move around a lot. My coolant temps hover around 195- 205 in summer Phoenix driving even though my needle shows as being at ¾ hot. When I drive it SoCal summer weather it’s under ½ so ultra gauge puts my mind at ease. It’s also good for seeing other real time live data and reading codes.
              Also if you’re in California, I would not hesitate to put in a 160-180 thermostat.
               
            • BigredLsc

              BigredLsc Active LVC Member

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              I see , this is my first summer with my LSC I had got the car in the winter of 2019 so I didn’t get to see how the car reacts in hot temps ... but lately and all last week it was 95-101 degrees outside ...so the needle goes this high let me show you a picture but it scares me and doesn’t seem normal because it if I leave the A.c weather in “Max AC” setting or “automatic” setting the needle will rise higher unless I turn off the AC and then The needle will drop slowly back to the middle of the gauge ... and wondering if I do put in 180 I don’t have to have the computer adjusted for the fans to come on sooner or something like that I rmbr reading about ? Also the needle only goes up while driving with the AC on if I’m sitting at idle the needle stays dead in the middle ! I appreciate all the knowledge by the way brotha !

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            • popstar

              popstar LVC Member

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              That’s barely one or needle marks past the middle, mines like that or slightly higher all the time in AZ summer. I wouldn’t worry about.
              I don’t know why it goes back to middle with the ac off. Mine usually comes down with the ac on. Off the top of my head I would think it has to do with engine load. Ac does put some load on the engine and these engines are very sensitive: temp goes up during increased load. I personally would not worry about it unless it goes up right under The red area. A tune is helpful but not necessary for a 180 thermostat. It will just take longer to get up to temp but that’s not a problem with these cars where we are since it’s already hot.
              No worries man. Glad I can offer some help.
               
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              • BigredLsc

                BigredLsc Active LVC Member

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                Well if I drive about 50 miles on a hot day any mileage after that with the AC on and I see the needle teeter that high like the photo I sent you , & keeping the AC on the needle will begin to go higher to the 3rd mark ! So I turn off the AC and the needle will then come down ... Although next time I’m going to just leave the AC on and see what happens once it starts teetering upwards and I’m going to put a 180 thermostat soon then
                 
                Last edited: Sep 21, 2020
              • BigredLsc

                BigredLsc Active LVC Member

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                see I have never had cooling issues with this lincoln up until I had to do the water pump I took it to some shop and they did the water pump , but the a**hole mechanic told me the radiator was full when I asked him is the car ready ? He said yes and I drove off pretty fast From his shop and he didn’t even fill any fluid at the crossover tube, smh, he only filled at the reservoir .. I drove off from his shop thinking everything was fine within 3 minutes needle was almost up at red but didn’t get to actual red but at the white line just before it .... so I hope it didn’t crack the head ... I checked water yesterday morning it was full in my resivor and then I was driving around All over 200 miles I put on the car yesterday and today in the morning I pop the hood and the resivor was low ? Only a waters bottle worth of water to fill it back to the ‘fill line’

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              • popstar

                popstar LVC Member

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                Man I feel your pain! You have to take it to a mechanic who specifically knows how to work on the 4v 4.6. I learned that the hard way too.
                I would redo the full coolant burp procedure yourself from when the engine is cold.. it might take several cycles to get all the air out. There should be a sticky here or on SVTPerformance for it.
                Although unlikely, it could be the water pump: did you get the upgraded motorcraft water pump (pw423) used in the 03-04 cobras and Mach 1s- the one with the extra ring around the vanes to prevent cavitation and push more coolant? Water pump without that extra ring on the vanes are not as efficient. Thats a good ford upgrade and they’re like $35 on rock auto. I found out about it from the mustang forums. I wouldn’t worry about a cracked head. You have to seriously overheat it to crack a head and it will warp before it cracks from what I read. I would try to get all the air out of the system over a few days of checking and adding more (distilled) water then go from there. Most people say if you’re running hotter than you’d, like turn your ac on, it kicks the fan on immediately and generally it brings the temps down. I bet the reason it’s acting funny is from air in the system. Now that I think about it, with your big ass griffin radiator it’s got to be air, cause you’d think it would run cooler than normal with that radiator.
                 
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                • xtriggerman

                  xtriggerman Active LVC Member

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                  When I put an all aluminum radiator in my 97 last year, I had a hell of a time getting the air out of it. After several burpings, I thought I was good and did a short 2 mile test, one mile in and it was red lined. Parked the car on a steep bank nose up and did the burping all over again, If you think you got it,.... do it again. Finally got it done and a factory Ford thermo keeps the gauge just below half in all weather, AC or not has absolutely no effect. Either in town or running 80 mph steady. When my blend door arm broke for the second time, I found there was a good bubble of air at the joint of the heater core pipe above the dryer. Despite that air there the engine temps were perfect. I still filled that pocket out anyway. With a new china blend door arm in place the AC/Heating runs perfectly.
                   
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                  • BigredLsc

                    BigredLsc Active LVC Member

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                    Exactly what I’m thinking someone suggested maybe air trapped in heater core but lately the weather hasn’t been so hot so it hasn’t been acting up ! Went 300 miles yesterday all together from Orange County to all over LA and it was fine AC on and off periodically. And with the water pump I got a generic brand from oriellys because the motor craft was a 3 day way part and I literally needed the pump in within the hour the bad one came out ... but it seems to be working fine ... i’m assuming if I did have a major problem the car would be overheating even if the temperature outside wasn’t hot right... and yea that radiator is really wide and holds much more coolent so ur defiantly right about that brotha , more space = more air to get trapped ... I have about 7-8 different threads open on my iPhone now of different explanations how to bleed the system smh I think I almost got it down lol
                     
                  • BigredLsc

                    BigredLsc Active LVC Member

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                    Yeah I think you might be right right there but wow only 1 mile and heated that much ? My needle only startS to fluctuate slightly after like 50 to 80 miles of driving and what kind of aluminum radiator did you put in and I have no heat right now AC works ice cold though
                     

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