Engine knocking sounds

Lincoln LS

  1. Morgynn

    Morgynn Active LVC Member

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    So the car has basically no gas left in it anyways, so I'm going to fill it with some premium, put some octane booster and fuel system cleaner in it and let it run then see where I'm at, if its still knocking I'll change the coils since I can get them for $50 shipped
     
  2. Morgynn

    Morgynn Active LVC Member

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    Let me know your thoughts on what this sounds like my car this time I got a better video
     
  3. Morgynn

    Morgynn Active LVC Member

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    Hmmm I filled it with some 94, put octane booster in, gumout fuel system cleaner, and 2/3 of a bottle of bardaal no smoke and it seems to have fixed the problem, I'm going to let it run for awhile and burn through some more gas, circulate that thick ass oil and see where I'm at
     
  4. joegr

    joegr Dedicated LVC Member

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    What out. You can damage the VCTs with too high of oil pressure (from too thick of oil).
     
  5. Morgynn

    Morgynn Active LVC Member

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    Okay so the sound is gone until the car is at normal operation temp and then it comes back..... let it cool down and it was gone again until It was warm, I'm lost at this point
     
  6. 04_Sport_LS

    04_Sport_LS Dedicated LVC Member

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    I STILL think you need to check oil pressure... both cold and hot engine temps. I'll bet the oil pressure is low after the engine warms up.

    I heard some noise in the video. Knock/rattle at idle... and the same clatter at the high rev point... similar to the other video of the other LS.

    Also sounded like some chain noise during rev and return to idle. Probably primary chains.
     
  7. Morgynn

    Morgynn Active LVC Member

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    I think you're right on oil pressure I just need to borrow the tool to check, I let it cool down and started it back up and it was fine until normal operation temp
     
  8. FDR

    FDR Dedicated LVC Member

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    Sounds like rod knock to me. The v8 can be checked pretty easily when you remove the spark plugs with a drinking straw and turning the crank by wrench. you can confirm by pressing down with a screwdriver once you find the piston with a delay. youtube it
     
  9. Morgynn

    Morgynn Active LVC Member

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    What should I search ?
     
  10. FDR

    FDR Dedicated LVC Member

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  11. 04_Sport_LS

    04_Sport_LS Dedicated LVC Member

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    How to check oil pressure. :rolleyes::D

    If it is a rod knock, (not convinced due to other engine noises), wouldn't it be best to figure out the reason why?

    And usually a rod knock will increase speed with engine rpm. I wasn't hearing that in your video. Just at idle, and the maximum you revved it to.
     
  12. FDR

    FDR Dedicated LVC Member

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    Mine didn't really make much knock noise as it revved up to 3k in neutral, but did distinctly make more noise over 2500 or so. Checking for rod knock is less messy than checking oil pressure, which makes it easier in my book. If the bearings are, in fact, spun, then it really doesn't matter what caused it because no one ever rebuilds these engines.

    An alternative way of checking is by unplugging one coil at a time and revving it the same way that makes the noise. Reconnect when moving to the next coil. By preventing the spark, ignition doesn't cause the piston to shoot down and slam the rod into the crank, which is where that noise would be coming from. If the PCM trips a misfire or coil circuit code and disables the injector on that cylinder though, you'll have to turn the engine off and restart with it connected. I'd rather skip the misfires and further rod damage and just go with the straw in the spark plug holes

    In hindsight, mine was probably killed by cold revving because I was a dumb punk kid. I wanted to show it off to an ex-LS owner. Then we heard "pulley" squeak. I wasted a bunch of time chasing down other potential causes because it seemed like it required higher RPM. Cell phone videos are atrocious for reproducing engine sounds, especially back when I did it on a flip phone. I don't think rebuild kits are even available, so it didn't matter why it had knock - the motor was coming out and being replaced. So now it sits under a tarp to be a matchup model for the mythical 4.2SC swap that never happens in the LS


     
  13. joegr

    joegr Dedicated LVC Member

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    It's safer (no chance of catalytic damage or ring wash down) and easier (no need to remove coil covers) to disconnect the fuel injectors one by one instead.
     
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    • 04_Sport_LS

      04_Sport_LS Dedicated LVC Member

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      It's not that messy. Unscrew a plug... and screw in a gauge. Low pressure could be a messed up cheap filter... or broken/weak oil pump bypass spring. If it is oil pressure related... every time the engine is run... more engine damage is caused.
       
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      • 04_Sport_LS

        04_Sport_LS Dedicated LVC Member

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        And if it is oil pressure related... the oil is probably having a hard time making it to the top end of the engine. This could cause top end engine noise, (which was an original complaint in this thread... or the sister thread).
         
      • 04_Sport_LS

        04_Sport_LS Dedicated LVC Member

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        Here's a short but good video on what happens/fails with the primary chain tensioners:

         
      • 04_Sport_LS

        04_Sport_LS Dedicated LVC Member

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        There are at least 2 people on this forum that have done 3.9 rebuilds. IIRC... they sourced the parts from Jaguar... for the 4.0 .
         
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        • Morgynn

          Morgynn Active LVC Member

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          Alright well I tried unplugging each injector and testing and the sound didnt change, so I tried the sparkplug test and nothing, I did notice that on both tests when I disconnected the second last injector and second last coil on the drivers side, I could hear some louder knocking at idle but it went away once it was hooked back up,
           
        • Morgynn

          Morgynn Active LVC Member

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          I dont want this to sound stupid but I dont have a way to test oil pressure right now so I just opened the oil fill cap while it was running to see if it would atleast spit some out because it probably should if it has good pressure right? Well nothing and some of the oil additive i put in was still on the cap so it looks like there is low oil pressure based on that but i have specific numbers, any car I've ever seen that has had the oil fill cap removed while running always spits oil out the fill hole..... i also still havent changed the coils but since the test i did changed nothing I'm assuming the coils are not the culprit, the next thing I'm going to do is check oil pressure and Jack it up and see if maybe its torque converter, or I hate to say maybe ruined cars that are rattling loud as hell... idk theres no check engine light and when I hooked up my new scanner today it didnt throw any codes anymore......
           
        • 04_Sport_LS

          04_Sport_LS Dedicated LVC Member

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          False.
           
        • 04_Sport_LS

          04_Sport_LS Dedicated LVC Member

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          That's because moving parts are slinging oil around inside the valve cover.
           
        • Morgynn

          Morgynn Active LVC Member

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          Fair enough
           
        • Morgynn

          Morgynn Active LVC Member

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          I can see parts moving but no oil.... weird? Or no
           
        • 04_Sport_LS

          04_Sport_LS Dedicated LVC Member

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          It's most likely not the torque converter. Think about it.

          From what you are now saying... the oil additive you put in... thickened the oil enough that the engine is now somewhat quieter... and evidently/supposedly eliminated all of your coil codes.

          You can rent an oil pressure gauge kit from your local parts store. You can keep it for a day... a week... a month... and when you return it you get your money back.

          The only other possible cheap fix... might be if the oil filter is defective. ESPECIALLY if it has ANY brand of oil filter from Wal-mart.
           
        • 04_Sport_LS

          04_Sport_LS Dedicated LVC Member

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          That's most likely because its not making enough oil pressure to feed the top of the engine.

          Keep farkin around and you're gonna burn it up!!!!!!
           

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