Engine knock on cold start up

Discussion in 'Modifications & DIY how-to' started by RoMe, Mar 4, 2010.

  1. RoMe

    RoMe Active Member

    Every morning it seems when I start the car I get a knock from the motor that sounds like rod knock but after about 30sec after idling it goes away. I never hear it during mid-day start ups even after the car has been sitting for a while so far only in the morning. After doing some research the only thing that I can find that may be the issue (with my fingers crossed) is the timing belt tensioner needs to be adjusted. This seems to be a problem with WRX's/STI's with my mileage around 50-60k.

    I just drove the car to Fl changed the oil while I was down there and it was clean the car throws no codes and drives absolutely normal.

    Thoughts and suggestions are greatly appreciated.
     
  2. nsvwrx

    nsvwrx Active Member

    I hear it in mine from time to time.. didnt think any of it.. 05 wrx 50k miles.
     
  3. kingwrex

    kingwrex Supporting Member

    yea, timing belt tensioner is a probable cause. if you can check with some chassis rears of some sort and put it on the front cover when started and listen to see if its coming from the behind the front cover.
     
  4. Alex

    Alex Community Founder Staff Member

    Wirelessly posted

    Say what? Haha.
     
  5. Trey

    Trey Active Member

    I think he means a stethoscope on the timing cover.
     
  6. BKiller

    BKiller Active Member

    King must do some magic stuff. I never even tried to use a Chassis Rear to listen to a timing belt before!
     
  7. goixiz

    goixiz Active Member

    what oil and filter are you using ?
     
  8. RoMe

    RoMe Active Member

    Rotella t6 5w-40 and oem blue filter.
     
  9. kingwrex

    kingwrex Supporting Member

    ok, i meant to say chassis ears or a stethescope, just had a brain fart/ fat finger typing.
    geez, talk about giving a guy a hard time.
     
  10. pEd

    pEd This ain't no Piccadilly!

    ^^ at least you're not typing in all CAPS and yelling at us :)
     
  11. integroid

    integroid Supporting Member

    That's is the root cause of all your problems. Honeywell made crap:) JK

    Seriously though Rome, you should be buying the black H6 filters for your car:)
     
  12. WJM

    WJM Banned

    Timing belt tensioner. There is no adjustment to be made on those, its a sealed unit.

    If it was a rod knock...well...its not going to be there for 30 seconds and go away.

    But if the tensioner is knocking for that long I would stop driving it until you fix it. You dont want the belt to jump and bend valves.
     
  13. nsvwrx

    nsvwrx Active Member

    Oh will. why wont you come back to GA.
     
  14. Bug-Rex

    Bug-Rex Active Member

    Mine does it when the temp is around 35ish. Definitely piston slap for me because it goes away after it runs for 5-6 minutes and definitely sounds like pistons/rods/something internal. Thankfully the temperature is rising slowly but surely so this won't happen until next winter.
     
  15. integroid

    integroid Supporting Member

    Do you have a built motor? You shouldnt get any piston slap from stock pistons.
     
  16. Matt

    Matt Think before you post Staff Member Supporting Member

    I don't think it should also do it for 5-6 MINUTES. Maybe 10 - 15 seconds at most.
     
  17. integroid

    integroid Supporting Member

    Nah, the cars I have heard slap for a few minutes. Mine has a slight tap for at least 2-5 minutes when the engine is really cold
     
  18. Matt

    Matt Think before you post Staff Member Supporting Member

    but his motor is stock...not built
     
  19. WJM

    WJM Banned

    Stock EJ205? Those will have piston slap under some conditions when cold. The cast pistons have a higher expansion rate than the hypercast, but less rate than the 4032 alloy and 2618 alloy.

    Just about every stock EJ205 does this and its normal. Most people do not hear it at all, its a rather minimal noise that you have to be listening for to hear.

    See above.

    See above.
     
  20. Bug-Rex

    Bug-Rex Active Member

    Yeah stock ej205. Thing is, you would have to be deaf to not hear mine. Its not just that its my car so I think it is really loud, when the windows are up and I am letting the coolant heat to about 70f before I start driving, it sounds like a small hammer hitting my block.

    Could be a partially spun bearing, but it only does it when its really cold out. Anything above 50f and it sounds just fine. It has never eaten a drop of oil and I have checked the oil every 2 days since I have owned it. I drive it pretty normally too. Never go above 3k until my coolant is up to about 180f, and after completely warm I never rev past 5k.

    Who knows. Its just a car though. Thats what I have to tell myself. No worries.
     
  21. integroid

    integroid Supporting Member

    I dont think that is Piston Slap. See King's post above about the tensioner.
     
  22. RoMe

    RoMe Active Member

    Just started the car for the first time today and nothing it sounds normal. Im taking it to Allpro in a bit to see what Brandon thinks about it.
     
    Last edited: Mar 5, 2010
  23. Matt

    Matt Think before you post Staff Member Supporting Member

    it's the cold. ;)
     
  24. WJM

    WJM Banned

    Same symptoms as other EJ205s with the same complaint...the noise is loudest on the cylinder wall areas when you listen with a scope. My wife's car is pretty loud when its stone cold and its colder than 50F, just like yours.
     
  25. Bug-Rex

    Bug-Rex Active Member

    Cool cool. I was never really worried about it. Just thought I'd share for some feedback for Rome. I lost interest in worrying about my car and decided to start enjoying it. Just routine maintenance and I'm good to go.

    I am still a stickler for oil levels though.
     
  26. It might be a really small midget inside with a ball peen hammer pissed off when it is to cold, put a barbie scarf in the crank case so he will stay warm and not be mad all the time. Geees some people!
     
  27. Bug-Rex

    Bug-Rex Active Member

    Thats what I came up with after my diagnosis. I cover it with a paper towel to stay warm. :rofl:
     
  28. WJM

    WJM Banned

    It's a JAPAN-MAN trying to get back home. But yes, when he is too cold he gets his hammer out to complain.

    The problem is, if you let him out and he goes back home, the engine will not run anymore.

    After all, SUBARU engines run only due to the JAPAN-MAN's black magic.
     
  29. JWX

    JWX Member

    Yep, when you let the magic out, they stop working.
     
  30. tolnep

    tolnep Member

    simply this..

    a small menkee.. they are here now because of global warming. they climb into your motor seeking warmth and perhaps small bananas..

    when you start your motor they tap on the cylinder walls hoping you will turn the motor off before they are crushed.

    best look for menkee fur and squised menkee parts in your exhaust to be sure..

    [​IMG]
     
  31. Hit the nail square on the head!:rofl:
     
  32. RoMe

    RoMe Active Member

    Well my jdm Man is on his way back to Japan as I type this, no worries though because I got a much younger version of him today thanks to the King!!
     
    Last edited: Mar 10, 2010

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