: Removing Seized Spark Plugs


bobby_t
03-11-2005, 21:39
trying to change my spark plugs but one is seized, whats the best way to remove, what can i use to lubricate it ? not wanting to break the spark plug and/or damaging the engine.

Steve220
03-11-2005, 21:51
how do you know its ceased? you sure its not just tight in the head? or is it turning but really tight?

Squirty a bit of penetrating fluid down there, wait a few hours then use a breaker bar on a proper spark plug socket and it'll come out.
Steve

IVAN MG
03-11-2005, 23:36
Nice cabby mate same as mine was,best colour IMO hope the plug isnt cross threaded or you might need a helicoil fitted, did you get it done yet?

IVAN

bobby_t
03-11-2005, 23:51
ive done nothing as yet, will wait till tomorrow morning before i go to work and spray it then, let it soak in during the time im at work then try it later......might sound stupid, whats a breaker bar ?

If all else fails got the RAC coming out on saturday to fit a new alternator might ask if he could try and loosen it.....

Amaranth_214
04-11-2005, 00:24
breaker bar = long pole...so you can put more force into the turn :D

Solstace
05-11-2005, 02:55
Yikes!!!

Er... might wanna be a bit careful about doing that...

I've had to get a helicoil put into the port of Spark plug No. 1, after someone gorilla'd the previous plug in. When we used a breaker's bar to get the old one out, it came out with half the old thread!!!

Use care, and prepare for a hassle when you have to find a way of re-coiling the thread... Took me >2 months to find someone who'd do it without taking the head off first!!!

The good news is, my baby's back on the road with no ill effects...

C.

1955diesel
05-11-2005, 07:59
Try it with the engine hot.

Fodenman
05-11-2005, 08:11
Try tightening first then undoing,if it moves give it another squirt,retighten then undo and so on till you work it out.If the thread goes you can get a kit to rethread with an insert with head in place.

HD-Tools 10798 813837 sales@hdtools.co.uk If it comes out ok but thread still stiff use a thread chaser to clean it out.Should get from Halfords etc.Put a spot of copper grease on new plugs and use torque wrench to tighten.Good Luck.

bobby_t
05-11-2005, 08:35
well i used penetrating fluid and its not budging, got he RAC coming out today to fix my Alternator, may ask if he could give it a try.......the saga continues.......

Dr Dave
05-11-2005, 12:44
Has it snapped off yet?

Amaranth_214
05-11-2005, 13:44
LOL Maj optimistic as ever i see

bobby_t
05-11-2005, 13:57
RAC guy wouldnt touch it, but said to use WD40 over the next month or soo ever few days and eventually it will loosen off.......

w4yne
05-11-2005, 14:49
If you do manage to get it out and the thread is a ruined a mechanic I know uses an old spark plug and cuts down the electrode and thread with an hacksaw so looking at it from the end you have two semi circles.

Slowly wind the cut plug in and out of the plug hole a few times and it will often clear the damaged thread enough so no other work is needed , worked ok for me on a Cavalier I bought witha cross threaded plug.

MGJohn
05-11-2005, 15:32
Try it with the engine hot.

Seconded... recommended....

MGJohn
05-11-2005, 15:41
If you do manage to get it out and the thread is a ruined a mechanic I know uses an old spark plug and cuts down the electrode and thread with an hacksaw so looking at it from the end you have two semi circles.

Slowly wind the cut plug in and out of the plug hole a few times and it will often clear the damaged thread enough so no other work is needed , worked ok for me on a Cavalier I bought witha cross threaded plug.

Also seconded ...:)

Done that several times over the years - it works! Most recently on an MG Montego Turbo Cylinder head which had one plug 'seized' in the head. Previous ownership/service had x-threaded that one plug in the alloy head and it was difficult to remove. Using the slotted old plug ploy cleaned up the threads nicely so that a fresh Helicoil insert was not necesssary! See pics - this was a head off the car but working carefully, it's quite feasible to do the job ON THE CAR. Here's the pics attached:

bw10030
05-11-2005, 16:31
Try Diesel down the plug hole, and leave overnight. Rather than use a steady build up of force, a sharp tap is usually better, as follows: get a good, tight fitting socket on the plug, having let it soak overnight in diesel. Try to use a fixed (not a ratchet) handle on the socket, and put some force on it in the 'unscrew' direction (i.e. hand force only, to take up any slack). Then hit sharply with a heavey headed hammer (a mallet is ideal), in the unscrew direction. If you are lucky, the 'shock' will be enough to free the plug.

A top tip for anyone replacing plugs, especially into alloy heads, is to use copper based grease sparing on the thred of the plugwhen inserting it - and do not overtighten! They only need 'nipping' up. If at all possible, spark plugs should be fitted as far as possible using fingers (i.e. no tools) to start the engagement of threads. This will prevent cross threading.

If you can't get it out, and there's no misfire, I would leave it be for the time being!

Dr Dave
05-11-2005, 17:01
If you can't get it out, and there's no misfire, I would leave it be for the time being!

Probably not a bad idea!

Great tip there MGJohn :)

misterreliable
05-11-2005, 17:54
It will have to come out eventually, then its back to square one again?? and with all the messing about with it as now, whats the ceramic like..

1955diesel
05-11-2005, 20:32
Don't use WD40, use penetrating oil or diesel. If it doesn't want to come out using reasonable force, leave it alone! You will eventually break it if you keep trying and then it may well be head off time!

cjmillsnun
05-11-2005, 20:49
Don't use WD40, use penetrating oil or diesel. If it doesn't want to come out using reasonable force, leave it alone! You will eventually break it if you keep trying and then it may well be head off time!


WD40 is penetrating oil, although I agree that plusgas is better.

Amagoza
05-11-2005, 23:21
WD40 is penetrating oil, although I agree that plusgas is better.

Is it? I thought it was a water dispersant.

Dr Dave
06-11-2005, 07:10
I have a 5/8" deep socket for removing tight spark plugs on a K - not had one break yet........


I've used an impact gun on them before, very gingerly mind!

misterreliable
06-11-2005, 08:38
An idea I use to avoid cross-threading is to lower your plug secured in the socket rubber to its point of contact then to very slowly turn in reverse over the hole till it gives a light click, (start of thread) then commence to fit and tighten..in the correct way. I do mine hand tight only..

bobby_t
06-11-2005, 09:56
well its not buding either way, TBH is not needing changed immediatly as the rest of the spark plugs look fine but i just got a new set of splitfire's and want to fit them, I was thinking if getting a long socket and using my torque wrench, or would that damage it, alternativly might take a garage to fix.....but as said before not needing to be done immediatly...............

alexf2828
06-11-2005, 10:30
spark plugs can last a fair old time so I would leave it till it really needs doing,if it shears off u have a problem,the only thing that seems 2 work on seized up things is heat so hot engine is best idea,doubt any penetrating oil will actually get on thread if its sealing cylinder compression!

katch
06-11-2005, 10:43
Depending on how much of a rush your in there is still one other option.

If you've tried wd - penetrating fluids, hot and cold running, deisel etc you can use a really really old trick that is generally left for un-seizing classic engines.

Engineers used to put hot oil into cylinders to heat the walls to create a tiny amount of space between surfaces, sometimes breaking the seize. that is non-threaded though, but it may work on the plug..

Putting small amounts of hot oil in the hole will heat the surrounding materials expanding them, after a minute you can try and remove the plug carefully, then leave it over night for the fluid to drain in the cylinder, new plug and your away.. leaving it to long will just heat all materials and the plug giving you no gains but there is a chance it'll work

Fodenman
06-11-2005, 10:44
I was thinking if getting a long socket and using my torque wrench,.


Do not use your torque wrench as a breaker bar.Would be like using wristwatch as a hammer. http://smileys.smileycentral.com/cat/4/4_2_108.gif (http://www.smileycentral.com/?partner=ZSzeb001_ZNxmk121YYGB)

stikler9700
23-10-2009, 18:30
Try it with the engine hot.

Just did that this morning with mine. I struggled for two hours with the plug. Then I put everything back togeter, drove it around the block, and then tried again. It came right out.