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How to remove seized glow plugs

Discussion in 'Engine, Drivetrain, Fuel and Exhaust' started by iainpatton, Jun 4, 2011.

  1. iainpatton

    iainpatton Member

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    Hello. My independent garage is too worried to force out two seized blown plugs. What is the latest thinking on doing this please?
     
  2. Steve@Avantgarde

    Steve@Avantgarde Forum Supporter Authorised Forum Supporter

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    Soak overnight in mech oil. Then get the engine red hot and then remove them with lots more mech oil. They will come out eventually but you just have to be careful!!!
     
  3. Rory

    Rory Senior Member

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    Isn't there a ssort of impact tool that vibrates them out?
     
  4. _Taz_

    _Taz_ Senior Member

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    NO NO NO !!!

    the failure torque of these is about 35Nm, you'll snap them like a carrot, simple.

    That said, they are "tougher" than you think.

    The key ( having done all 6 myself ), is :

    1) Soak for a few days with good penetrating oil, as you are trying to reduce the torque needed to undo the top section of the glow plug ( as it's in compression )
    2) DO NOT attempt doing this on anything other than a RED HOT engine.
    3) As soon as the engine is shut down, get to work, don't worry about it all being hot, that IS GOOD.
    4) Slowly apply a gentle torque to the glow plug ( if needed just rock it back and forth, GENTLY ), they WILL come loose.
    5) Loosen all 6 off at once, whilst the block is HOT, don't worry, as once they are free you can then loosen them off later.
    6) Practice removing the electrical plugs to the tops ( NO sideforce should be used, as this weakens the fitting ) : You could use a double bent piece of coat hanger wire to pull the plugs off.

    If you snap them, the work to remove it is quite alarming & you need specialist drilling jigs, else you'll scrap the cylinder head.

    :D
     
  5. Alex Crow

    Alex Crow Senior Member

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    some good advice on this thread (eg remove when fully hot), but ignore the last bit that that i have quoted.

    removing sheared glow plugs is not difficult, and there IS dedicated equipment designed for the job (have a look on youtube for, eg, 'mercedes glow plug removal'), but it's not necessary - there is a good diy guide or two on, eg, peachparts.

    i typically charge 1 hour per sheared glow plug to remove, clean out and fit new, this price drops for multiples. i do NOT have specialist jiggs and drilling equipment, and have never failed to extract one.
     
  6. wiseman

    wiseman New Member

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    There is a product called In-Force by a company called Bgproducts. It is very good at penetrating very siezed items.
    Its rather bizarre stuff to use, it foams up and has a strange clinging affect to avoid run off, but it is a penetrating oil. I have used it to remove very stuck injectors in dci Heads etc...Amazingly affective.
    Try heating them with a blow torch maybe too
    Good luck
     
    Last edited: Jun 5, 2011
  7. Frontstep

    Frontstep Senior Member

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    Two issues really the thread gets corroded and the element end gets coked up.
    You can reach some of the thread with various potions but getting at the coked up end is tricky I have put the piston on TDC and filled cylinder up with carb cleaner in desperation.
    Gently rocking first clockwise then anti with plenty of proper penetrating oil (I used to make my own with acetone and auto fluid etc it seemed to work) with a small T bar worked well for me.
     
  8. _Taz_

    _Taz_ Senior Member

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    @ Alex, fair point fella, however I just want peeps to understand it's not a simple case of a pistol drill, easy-out & a cold chisel ! :p

    And to be fair, you are not your average DIY-er :cool:

    Just a warning to research the removal, heaven knows even I was nervous doing the 1st one !

    Sounds so simple ? 8mm socket, turn anti-clockwise, replace glow plug, how hard can it be ?

    erm... I'll go back to my corner.... :D
     
  9. Alex Crow

    Alex Crow Senior Member

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    that is cool taz, you are quite right to voice the words of caution.

    on a side note it is hard to know just how much expertise, knowledge and equipment posters have. i have recently been abused for giving information on a thread here, which was not correct for the vehicle the original poster had. if we had an obligation to stand by our advice, with the responsibility for any mistakes made by people following our advice, i for one would never post again. anyone seeking free advice on internet forums, or anywhere else for that matter, must understand that genuine mistakes and omissions are commonplace, and that they must be sure themselves that any work they undertake (eg changing brake pads) or any advice they follow (eg recommendation to go to a certain garage) is at their risk.
     
  10. Number_Cruncher

    Number_Cruncher Senior Member

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    Your side note, AP, is, in my opinion rather important.

    I'm not sure that the law would approach this with an attitude of common sense, particularly when the advice does come from people who are obviously qualified.

    For this reason, I think it is quite bold for qualified people to give advice on the internet. For my part, this is one reason why I rarely stray away from or beyond recommending MB materials and procedures. Many may think it unecessarily timid of me.

    Perhaps if I were posting on an electronic goods web forum, I might be blindly happy about recommending corner cutting on safety critical systems when mending tellys, as I would be safe enough hiding behind the cloak of incompetence and amateur status.

    Is there anyone on the site who could help with clarifying the legal status of our posts - or, would legally qualified members be put off posting such advice for fear of any possible consequences?
     
  11. Alex Crow

    Alex Crow Senior Member

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    :grin: had to read that one twice george.

    EDIT: the liability of the forum owners, hosters, mods etc must also be an issue. anyone know of a precedent on this vis litigation?
     
    Last edited: Jun 5, 2011
  12. dieselman

    dieselman Senior Member

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    If they are really stuck don't switch the engine off until the plug is well undone. This keeps the cylinder-head hot, the shock of combustion gives a little additional shock and the expanded gasses blow coke out of the threads.
     
  13. Alex Crow

    Alex Crow Senior Member

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    if following DM's advice beware, undo the plug fully and you have a dangerous situation!
     
  14. dieselman

    dieselman Senior Member

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    ^ Thanks Alex, I was going to write a cover-all, but thought it wouldn't be necessary.

    On occasion when the coke stops the plug being withdrawn even after it is undone, I have placed a socket and ratchet back onto the plug then runt he engine while turning the plug so the gasses blow the plug out.
    just stand out of the line of fire and it is safe enough.
     
  15. Olivier

    Olivier Senior Member

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    I did run the engine to spat a plug that was coked in, but never try to turn it, DM you are the Man, a wee scary tho...
    The pressure usually spat the bugger in no time, with a very loud bang ;)
     
  16. Rory

    Rory Senior Member

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    If that was aimed at me, then perhaps it wasn't clear that I meant more vibration than impact!

    This isn't the exact tool that I've seen elsewhere (it might be a custom MB special tool that I saw?) but it's the same basic idea: http://www.youtube.com/watch?v=vkr7CQP7vWs
     
  17. _Taz_

    _Taz_ Senior Member

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    Rory,

    No mate, not aimed at you fella, just a General warning. :D

    Good vid, however it just fills me with dread, I'd like to see that Sykes unit calibrated on a proper torque meter, 10Nm is tiny to measure... :eek:

    Let alone the U-Joint used, which actually can Increase torque....

    Looks ok in the Vid, but me, being ME, how do I know that is not staged ?

    Torque pre-sets are a very grey areas, at work, we only stud tension big stuff, as torque values are unreliable, turn of the nut is more reliable, but obviously not in this application ! :)

    "If" it came with a UKAS cert / something from the National Physics Lab ( that I use for stuff ), then "perhaps" I'd use it on the block of a 55 plate car with medium - high mileage.

    I'm definitely NOT saying it's no good, it certainly looks ok, but once you've pressed the trigger and remembers you set it on the wrong button, it's too late :(

    Good find though ! Part of what this forum is VERY good for. :D

    Again, it's only a glow plug, but the workmanship is as only as good as the person doing the work I suppose, hence why I guess a good indie is worth his / her weight in something valuable !

    HTH :D
     

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