Anonymous
Anonymous asked in Cars & TransportationMaintenance & Repairs · 1 decade ago

Blowing Spark Plugs Out of Head...???

We have a 02 5.4L Ford in the shop... the complaint was "loud exhaust, and running rough"... well after a few minutes of looking into it, we found it blew out a spark plug, bank 2, which explained the loud noise (combustions, not exhaust) and obviously it's missing due to the plug being out...

Ok, so we start by checking threads, plug damage etc... all ok, other than the coil pack mounting tab broken. We figured maybe it loosened up, and backed out, we've seen this before, so we installed new as needed.

2 days later it's back, same issue. We go straight back to that plug, and sure enough, blew it back out... except now there's witness marks... stripped threads, bottom of plug had impact damage etc. Ok, so I've seen this too, but have never tore into it to locate exact cause.

In theory, I could imagine a couple things... piston slamming into it, and forcing it up and out... or even a valve sticking and pressure from the combustion or exhaust stroke pushing it out... any other ideas?

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  • 1 decade ago
    Favorite Answer

    I have delt with several of these at the Ford dealership here. Ford's stance on it is that when plugs get replaced someone isn't putting antiseize on them. (???) Let me guess, second or third plug back right? The dealership here will pull the head, and have hardened thread inserts put in on all four, then put the head back on. The only thing we ever came up with was that the aluminum threads were cut wrong, or the aluminum wasn't heat treated correctly. Get used to this one, you are liable to see more of this.

    BTW, how many miles were on it? Over 100K? Or close to that? Here's the latest TSB...

    TSB 07-21-2

    10/29/07

    4.6L 2V, 5.4L 2V, OR 6.8L 2V - SPARK PLUG

    THREAD REPAIR PROCEDURE - NOT COVERED

    UNDER NEW VEHICLE LIMITED WARRANTY

    FORD:

    1997 Thunderbird

    1997-2004 Mustang

    1997-2008 Crown Victoria

    1997-1999 F-250 Light Duty

    1997-2004 Expedition

    1997-2008 E-Series, F-150

    1998-2004 F-53 Motorhome Chassis,

    F-Super Duty

    2001-2005 Excursion

    2002-2006 Explorer

    LINCOLN:

    1997-2007 Town Car

    1998-1999 Navigator

    MERCURY:

    1997 Cougar

    1997-2008 Grand Marquis

    2002-2006 Mountaineer

    This article supersedes TSB 07-15-2 to update the vehicle model years.

    ISSUE

    Some 1997-2008 vehicles equipped with a 4.6L 2V, 5.4L 2V, or 6.8L 2V engine and aluminum cylinder heads may experience a spark plug port with stripped or missing threads.

    ACTION

    Follow the Service Procedure steps to correct the condition for non warrantable repairs.

    SERVICE PROCEDURE

    Ford Motor Company now authorizes LOCK-N-STITCH aluminum insert and tool kit as a proper repair procedure.

    Follow the procedure included in the tool kit for using the tools and inserts. Tool kits and inserts can be ordered from Rotunda by calling 1-800-Rotunda (768-8632). Choose option two (2), part number 302-00001.

    NOTE FORD MOTOR COMPANY HAS DETERMINED THAT REPAIRS MADE WITH THESE ALUMINUM INSERTS AND LOCK-N-STITCH TOOLS DO NOT AFFECT THE HEAT TRANSFER FUNCTION BETWEEN THE SPARK PLUG AND THE CYLINDER HEAD.

    NOTE THIS PROCEDURE IS NOT AUTHORIZED AS A FORD WARRANTY REPAIR. FOR VEHICLES WITHIN WARRANTY, REPLACEMENT OF THE CYLINDER HEAD IS RECOMMENDED.

    NOTE THIS IS THE ONLY FORD AUTHORIZED PROCEDURE FOR SPARK PLUG THREAD REPAIRS.

    NOTE THIS PROCEDURE IS AUTHORIZED FOR ESP REPAIRS AND RETAIL REPAIRS.

    WARRANTY STATUS: Information Only - Not Warrantable

    Source(s): ASE 15 years
  • 3 years ago

    Blown Spark Plug

  • Dale
    Lv 4
    4 years ago

    N O N O N O It WILL not. There was troubler before the plugs were changed. HAve someone REMOVE those new plugs and look for DISCOLORATION On them. The tips should be WHITE with no unusual coatings or coloration. If there IS < then you MIGHT have aleaking head gasket. The thing about THOSE is that often times just changing the HEAD BOLTS will cure the rpoblem. The reason is VERY SIMPLE. Over time,s the head bolts S T R E T C H. They are supposed to do that. After many years, they get tired and MAY cause a leak. Replacing the HEAD BOLTS is required anyways if you remove the head. If you REPLACE the bolts and it DOES work, then you CAN RE-USE THEM! YOU SHOULD use ONLY the factory COOLANT in there. GOOD LUCK!!

  • 4 years ago

    For the best answers, search on this site https://shorturl.im/avn4m

    A spark plug is either fitted, or not - it can't be ill-fitted unless: a; grossly overtightened b; not tightened sufficiently c; it's the wrong plug for the car. None of the above would cause the head gasket to fail,apart from possibly c;, but, as someone has already said, if the plug is too long a reach, it could potentially damage the piston(s) and also possibly the valves and the head. If they insist that the head gasket has blown because of c, above, then your cylinder head would be completely knackered. In summary, take it to another garage.

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  • Anonymous
    4 years ago

    This Site Might Help You.

    RE:

    Blowing Spark Plugs Out of Head...???

    We have a 02 5.4L Ford in the shop... the complaint was &quot;loud exhaust, and running rough&quot;... well after a few minutes of looking into it, we found it blew out a spark plug, bank 2, which explained the loud noise (combustions, not exhaust) and obviously it&#39;s missing due to the plug...

    Source(s): blowing spark plugs head: https://tr.im/Fbs2D
  • 1 decade ago

    If it had impact marks there is only one thing that can hit it, the piston. Question is was that the first time problem or a result of the problem the second time? It could have been a defective injector causing the first, not real bad but enough to continuelly wash down the piston bearings causing the second, an impact to the spark plug.

  • Anonymous
    1 decade ago

    Too much fuel, causing a 'hydro-lock' condition. But of course it won't lock up, there's just too much momentum.

    Since this is happening during the combustion turn, all valves closed and piston close or near TDC, so....only way out is through the weakest link....the spark plug hole.

    Leaking injector maybe?

    Just an idea....

  • Anonymous
    1 decade ago

    if the plug is the same length as the others, then the piston would be doing it to all the other plugs too. try this, get a new plug and use thread lock and see if it still blows out. test drive it and see if it blows.

  • 1 decade ago

    any chance of a crack or a casting flaw that will not allow spark plug to seat proper?if you have a theory on the piston slapping it did you examine the top of piston for marring?it may be some weird case of serious detenonation,or even a timing issue?not sure really,just tossing ideas your way.

    Source(s): x import tech
  • tony s
    Lv 4
    1 decade ago

    Lean fuel injector or vac. leak causing excessive temp in cylinder. If valve were a problem it would not build compression, if piston hit plug you should have a knock on last trip.Another possibilty would be sticking injector or bad pressure regulator as these can cause hydraulic lock on cylinder

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