Engine knocking sounds

Lincoln LS

  1. Morgynn

    Morgynn LVC Member

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    My car is a 2005 Lincoln ls v8, it has been knocking when accelerating over 3k rpm, I looked and looked for two weeks online and from what I could tell from videos and clips of different possible reasons why it could be making this sound it should have been the timing chain tensioners but when i took the valve covers off I could see that the car is in perfect timing and has new tensioners already, I'm just about to put that car back together but I'm curious what it could.be now, it's not too loud and the car runs great with the issue but I havent been driving it, I'm thinking it could be a couple coils or maybe spark plugs, could it be my flexplate/ tourque converter? Any suggestions on how to get this figured out so I can drive my car again??
     
  2. 04_Sport_LS

    04_Sport_LS Dedicated LVC Member

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    So how could you tell that everything was in perfect timing just by pulling the valve covers?

    Everything indexes off the crankshaft, and there are actually 4 timing chains and 4 tensioners. 2 primary, and 2 secondary, (which are the ones you looked at).

    You didn't state the milage on the vehicle... or if you were the original owner... and if any known work has been performed on the engine.

    Sounds to me like there was a previous owner that replaced or had the secondary chains and tensioners replaced due to an issue... but didn't have the primary chains and tensioners replaced because it is a much more labor intensive and costly job.
     
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    • FDR

      FDR Dedicated LVC Member

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      Typically, chains rattle and spun bearings knock. How's your oil? Does your accessory belt and belt tensioner look to be moving smoothly? If timing jumped, you'd probably notice a feeling like a constant misfire
       
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      • joegr

        joegr Dedicated LVC Member

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        I doubt that the tensioners have been changed. Mine look new at 190K+ miles. Your gen II has the newer design tensioner that don't ever seem to be a problem. Your reading mislead you. Tensioners aren't a problem on gen II, and if they were, it wouldn't be a knocking sound.
        Did you check your motor mounts?
         
      • Morgynn

        Morgynn LVC Member

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        The tensioners definitely have been already replaced, but no I didnt check motor mounts yet
         
      • Morgynn

        Morgynn LVC Member

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        It doesn't seem like a misfire, and oil is fine, the belt is also good but I have to put some parts back on the car before I can start it and check the tensioner
         
      • Morgynn

        Morgynn LVC Member

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        I dont know anything about the previous history of this car as the last owner thought it had a blown engine because he couldn't start it but the fuel cut off was just on for some reason, anyways it has 179k km and from what I can tell it completely stock besides new plugs at some point but needs new again and that's about it, the sound only happens when you rev above 3k rpm

         
      • joegr

        joegr Dedicated LVC Member

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        How can you tell that?
         
      • Morgynn

        Morgynn LVC Member

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        The upper secondary ones have atleast, I can see that they aren't the stock ones
         
      • joegr

        joegr Dedicated LVC Member

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        Pictures?
        It would be very unusual for a gen II tensioner to fail or be replaced. I'd also surprised that there are any non-stock options for those. I have over 200K miles (322K Km), and mine look new.

        Anyway, I hang on this only because it would be very rare for any timing work to have been done. If it was, whatever caused that (lack of oil changes?) could have caused bearing problems.
         
      • Morgynn

        Morgynn LVC Member

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        I already put the valve covers back on here is a video of what is happening, is not my car but mine is doing the exact same thing and making the same sound
         
        Last edited: Apr 30, 2019
      • Morgynn

        Morgynn LVC Member

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        It sounds fine until it is revved to 3k rpm
         
      • jmeecer

        jmeecer LVC Member

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        Sounds like a busted flex plate (flywheel).
         
      • Morgynn

        Morgynn LVC Member

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        that's what I'm thinking aswell since it runs perfect
         
      • 04_Sport_LS

        04_Sport_LS Dedicated LVC Member

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      • LS Nuts

        LS Nuts New LVC Member

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        Acouple of thoughts on the knock. Have you tried disabling individual coils to see if the knock gets quieter or disappears? If so, likely a rod bearing. Another cause can be a large carbon deposit that actually contacts a piston. stethoscope time. Possible check the flex plate by accelerating and braking simultaneously, on the road ,if needed.
         
      • 04_Sport_LS

        04_Sport_LS Dedicated LVC Member

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        And as another thought... the Gen 2 engines have been known for a rattle at startup... which is an issue with oil bleed down of the cam phasers.

        It's possible that the cam phasers or VVT solenoids could be an issue... but this would still most likely fall back to probable low oil pressure. And IIRC... the cam phasers are, (normally if functioning properly), in full advance by 3k rpm.

        So AGAIN... the first thing I would be checking is the oil pressure.

        Never heard of coils, (electrical), fixing a mechanical sound/issue.
         
      • 04_Sport_LS

        04_Sport_LS Dedicated LVC Member

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        I also don't recall any mention of diagnostic codes.
         
      • joegr

        joegr Dedicated LVC Member

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        It's much safer (and slightly easier) to unplug the fuel injector instead. If you unplug the coil, then raw gasoline gets to the cats and can damage them. There's also a very slight danger of washing down a ring.

        He's not talking about the coils being the problem or the fix. He's saying that if you prevent combustion on a cylinder, it reduces the stress on that rod bearing. It's a diagnostic trick to try to find which one is bad.
         
      • 04_Sport_LS

        04_Sport_LS Dedicated LVC Member

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        I agree with what you said about disconnecting the fuel injector instead of the coil.

        However... I think you misunderstood my comment on the coils.

        That comment was directed at the OP... since he seems fixated on swapping out the coils first... instead of checking oil pressure and internal components.

        Also... my guess would be that the OP says the secondary tensioners are new... either because he replaced them... or the previous owner said be they did, (or showed him a receipt.

        I don't think we are getting the full story.
         
      • 04_Sport_LS

        04_Sport_LS Dedicated LVC Member

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        And yes... I get the trick/idea for checking the rod bearings. It's a good one.
         
      • joegr

        joegr Dedicated LVC Member

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        I agree. It doesn't add up at all. I wonder if we will ever hear more from the OP?
         
      • 04_Sport_LS

        04_Sport_LS Dedicated LVC Member

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        Yeah well... he has stated his plan of attack. Post #31 from the other thread he started:

        " The obd reader told me that they are all no good that's why, I've seen another guys ls make the same noise and it was from the coils, others cam tensioners, others its valves, sometimes oil pump, or even rod knock so I am trying to slim down what it might be, I figure the coils are a good start, I'll check the oil pressure aswell, I just bought and gapped new plugs for it aswell, it did sit for an unknown amount of time before i got it but I'd guess atleast a year, the gas it probably not helping out with the whole situation I'm sure "
         
      • Morgynn

        Morgynn LVC Member

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        I did try pulling each coil but nothing changed with any of them.
         
      • Morgynn

        Morgynn LVC Member

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        I want to swap coils because the only codes i got when i used my scanner were for every single coil which i agree doesnt seem right, i checked the valves and they are fine, i have new plugs, i have not had a chance to check oil pressure but that is definitely next on my list, im going to coils regardless because i have a connection that can get me all of them brand new for $50 so why not lol it does rattle on start up and my friend who is a heady heavy duty said it could be oil pump, i dont think it sounds like the flexplate but who knows, its not the belt tensioner rattling i can see that myself and for the chain tensioners i k ow they have been replaced because i know what the originals look like and i know what the replacement onea look like and they are 100% the replacement ones im not sure if they needed replacing or not but i can see that someone before me did the work, i have literally no history on the car because the guy i got it from doesnt know the difference between a wrench and a hammer lol i got it for $250 and he told me the engine was toast and wouldnt start but it just needed the battrry charged and the fuel cut off switch was on so i turned it off smd it fired right up everythung works it just has this sound over 3krpm, its only got 179k km on it and its in great shape so i cant imagine its anything too major i just want to get it figured out so i can drive it lol i hope that answera some questions, sorry i havent replied recently ive been super busy i just got back working fulltime and with two kids under 5 i dont have as much time as id like for workin on cars as i used too
         

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