Engine 2003 Mustang Gt 4.6 - Knocking/rattling Noise @ Startup & Higher Rpms

Discussion in 'SN95 4.6L Mustang Tech' started by Quick03GT, Jun 7, 2014.


  1. Quick03GT

    Quick03GT New Member

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    ok here is the issue, in the mornings or when i let the car sit for awhile i go out to start the car up it makes a loud knocking noise then goes away, but when you raise the engine rpm up to about 1,500/2000 rpm the knocking get's louder sounds like it coming from the passenger side of the car.

    I have already replaced the timing chain guides, tensioners, etc.
    I have already unplugged each injector the noise does not change or go away
    It sounds like its coming from the front of the car right by the timing chain cover and the valve cover.

    This noise happened out of no where going home from work and started making a noise, sounded like it was low on oil but that was not the issue.


    The car is not blown or has any kind of power adder of the sort. it's pretty much a stock engine with about 180,000 miles..

    any kind of help or what to look for would be appreciated!
    thank you in advance..

    p.s. if a video would help please let me know
     
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  2. Quick03GT

    Quick03GT New Member

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    here is the video of the noise..

     
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  3. jka

    jka Member

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    It sounds like the timing chain and guides/ tensioner.
     
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  4. Noobz347

    Noobz347 Stangnet Facilities Maint Tech... Er... Janitor Admin Dude

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    Moved your thread over to the SN95 Tech forum. You stand a much better chance of getting a response here.
     
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  5. trombonedemon

    trombonedemon Well-Known Member

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    Rod bearing, you can check those by removing the oil pan, but the engine needs to be supported and engine mounts removed.
     
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    Last edited: Jul 28, 2014
  6. 1987stangman

    1987stangman Member

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    How does the engine run as a whole? Could be a rod bearing, or it could be a lash adjuster or the chains. Your post says you have redone all that though.

    If it was me I would get a mechanical oil pressure guage and hook it up to see what the physical oil pressure was. The stock guage is not much help as the oil pressure could be low it would still read normal. That would help you determine if you possibly spun a bearing. If the oil pressure is good i would pull the cam covers and the front cover and inspect.
     
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  7. stangr5oh

    stangr5oh Active Member

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    Have you checked your COP's, I would assume by the list of things you already replaced you have not. I have run across this very issue on a few cars. If a COP starts to fail, it will not fire correctly in a single cylinder or cylinders. At first it will sound like a timing chain but after a few quick seconds it will go away. I would before doing anything else check all COP's. If they get real bad you will also get a CEL on a bank running lean issue also. Also a torn COP boot will do this too. The boot get very hard over time from heat and crack or split open and causing the spark to bounce off the cylinder COP port. But my first avenue of approach as mentioned before is to check your COP's (Coil Over Plug) and also inspect each boot for rips, tears or torn. After a 180,000 plus miles, it is very reasonable to assume you may have a failed COP(s).

    Your video does sound like a rod bearing, but before you go diving into something significant such as your internals, check the externals first. Throwing parts at it like you have been can get very expensive and in the end still have the issue at hand. So start inspecting and checking parts before going out to purchase. Hopes this helps. Post your findings and we will go from there.
     
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    Last edited: Aug 5, 2014
  8. horse sence

    horse sence Please don't call me Mom SN Certified Technician

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    When those coils go they go all at once .Had one go out on my 2000 F150 ,it made a knocking sound at first like heavy pinging and then it started missing .
    I had to drive it that weekend ,about a 200 mile trip ,and on the way back another coil went .This time it started back firing .I barely made it home . Changed the two coils ,one had a pin hole burned in the boot ,and it was good as new . Mine would not show on a scanner other than a intermittent miss.
     
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  9. TheViking

    TheViking New Member

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    To me it sound like a valve problem, might be one of your valves thats stuck.

    I would suggest a compression test, with a comp test you can exclude alot of issues.

    I would also check camshaft for exessive wear.
     
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