General Stuck Spark Plug

[CasLad]

I tried to change my spark plugs for the first time on my Seicento 2002 (1108cc). It was my first time, not the cars! I have had the car 18 months and have been working through how to do my own servicing. Since I didn't know when the car last had its spark plugs changed, I thought I'd do it as per the service manual, even though the car is running fine.
Anyway, the first plug that I tried was seized/stuck and it broke the cheap plug extractor tool that I'd bought from Halfords (which I took back). Someone told me that the cause of it being stuck was likely that it is metal on metal and that it has welded itself on, and that I need to be careful to avoid breaking the plug off.
Can someone advise me how best to go about removing this plug please? Would WD40 be any use? Or is it best to try and move it a small turn then reverse, then turn again, etc.? I am going to buy a ratchet socket with long bit and try again, but didn't want to break the plug off, obviously.
Thanks. Andrew

 

[glenn2602]

Go easy .. if you manage to break the spark plug you'll have less to smile about.

Try wd40 by all means, but when you get your improved spark plug wrench (try a proper spark plug socket..) .. don't try and jerk it to free it. No brute force.

Put the socket on the spark plug and put gentle pressure on the ratchet as if you were tightening it .. That's gentle pressure .. don't try and tighten it .

Then put gentle pressure in the opposite direction .. try a rocking motion using gentle pressure clockwise then anti clockwise. Keep repeating and keep putting on a tad more 'undoing pressure'.

The plug will come out. It may have been overtightened in the first place. Gently does it .. once you break the seal caused by the threads it'll come out.

Keep us posted..

 

[Brooky]

Try getting the engine up to temperature and then trying it.
A decent socket shouldn't break.

WD40 won't do much, use Plusgas if you are going to try anything, WD40 is not a penetrating oil.

End of the day, there are plenty of centos being broken for parts, a head should be easily sourced.

 

[g8rpi]

Plus Gas is about the best but the makers of WD40 also make a penetrating oil spray (you can make your own from a 50/50 mix of acetone and automatic transmission fluid if you happen have them avilable). If possible put some down the plug recess the night before. Start the engine to warm it (does not have to be fully hot) and try loosening the plugs. A "breaker bar" or sliding T bar is better than a ratchet if you have one. You can break ratchet with too much force.

Robert G8RPI.

 

[David C]

As above, don't use a ratchet to loosen tight stuff, use a breaker-bar, ideally a long one (ie 60cm).
Much easier to use controlled pressure on a long lever than a short one.

So go shopping and get a long breaker bar, a spark plug socket and an extension bar.
Plus the PlusGas.

 

[Steve145]

I've always favoured a sliding 'T' bar, centred, held with one hand on each end of the 'T', this way you are only applying a twisting action and not levering the plug sideways, as can easily happen with a rachet or long bar, particularly if it's a deeply recessed plug and you're using a long extension.


Have to admit though, if it wasn't coming out with reasonable force, I'd probably give it a try with the impact driver on it's lowest setting.

Disclaimer - I've never tried an impact wrench to remove a spark plug, so I have no idea what would happen, but that's what I'd try if it were stuck.

 

[rallycinq]

Cillit Bang, the one with bleach in it is great for un-sticking things. Needs a good 24 hour soak, but will get injectors out of heads.

All above advise is good, gentle pressure, if using a breaker bar, make sure you hold the top of the extension in place to avoid twisting the plug.

D

 

[Ralf S.]

Disclaimer - I've never tried an impact wrench to remove a spark plug, so I have no idea what would happen, but that's what I'd try if it were stuck.

If you had, you wouldn't be suggesting it..

My tuppence worth... get a proper spark-plug socket, the shortest extension bar that will clear the rocker (a longer extension bar is more likely to put side-pressure on the plug)... and a long breaker bar... although the sliding T-bar suggestion is also a good one.

If you don't have many/any tools... look at Halfords Advanced range:

http://www.halfords.com/workshop-to...fords-advanced-28-piece-metric-socket-set-3-8

This set has a 3/8" drive ratchet (in which case you should buy a 3/8" drive spark plug socket and breaker bar, to go with it). 3/8" tools are lighter and easier to use than 1/2" drive.

They're ultimately less "heavy duty" than 1/2" ... but the Seicento doesn't have heavy duty components and, if you're learning DIY servicing, then as my old dad would say, if you need bigger tools, the chances are you shouldn't be doing that job..


Ralf S.

 

[Ralf S.]

Don't get overly panicked if you do happen to snap a plug.

In some ways without the top of the spark plug in there, it's easier to get a socket onto the hex' (once you've removed the bits of destroyed plug)... but obviously the car is un-driveable in the meantime, so it's best to avoid breaking anything.


Ralf S.

 

[g8rpi]

Cillit Bang, the one with bleach in it is great for un-sticking things. Needs a good 24 hour soak, but will get injectors out of heads.

All above advise is good, gentle pressure, if using a breaker bar, make sure you hold the top of the extension in place to avoid twisting the plug.

D

I hate Cillit Bang (wife loves it). Trouble with using it on the spark plug is getting the residue off so it does not cause on-going corrosion. any going down the hole will contaminate the oil. Maybe I'm oversensitive having worked on gas turbines where exposure to chlorine compounds usually results in at least new blades sooner than normal and often a loud, very expensive and sometimes fatal turbine explosion.


Robert G8RPI.

 

[Goudrons]

My old Cinq Sporting was the only plug thread I ever stripped myself.

I dealt with plenty of others that someone else had stripped, but that was my one and only!

The head is alloy and the plug threads are steel and the two different metals react with each other, it's called galvanic corrosion (better known as Land Rover disease)

You need to be careful with getting the old plug out.
Soaking as descrided and getting the engine hot should help, but try not to get carried away with a long breaker bar forcing the plug like Popeye after his spinach!
Old plugs that are stuck can snap off and cause a lot of agro.

When fitting new plugs, use a dab of anti seize compound on the new plugs threads.
Some don't like it, but I've always used Copperslip (since the above) and never had trouble, others will use some other stuff, but it should do the same job.

 

[portland_bill]

Most of the above advice is good, but don't try an impact driver. That would hit against the head, potentially damaging it around the plug seating.
Plus Gas, warm engine, and a T-bar is the best solution. Plus some swearing.

Might be a good idea to unplug the first injector and move the wiring plug aside.

 

[Steve145]

I think I've been misunderstood, by impact driver I mean an air or electrically driven shock gun, the kind tyre fitters use for removing wheels, not the sort you hit with a hammer.

I've got a spare head with plugs stuck in, maybe I'll give it a try and let you know what happens?

 

[portland_bill]

The spark plug metal body is not thick. They can fracture if excessive force is used, and this is very likely if impact forces are used. Gentle increasing pressure is best, and a T-bar will achieve this best by reducing the tendency to put sideways forces on it.

 

[blu73]

lots of sound advice here... but just to tack on the end here, don't put your new spark plugs in super tight lol

Maybe as a novice it would be best to use an actual torque wrench so you can feel how tight it should be. I'll be honest, i rarely use a torque wrench - there are times when you really need to but after a while you get a feel for how tight different things should be but as a complete novice I highly advise using a torque wrench and correct torque settings in the manuals for alot - most bolts do not need to be as tight as most people think, spark plugs included.

 

[Liquid Knight]

I have a narrow wall 1242cc FIRE on my drive and 866 cam' if you total it.

Good luck.

 

[Steve145]

I've got a spare head with plugs stuck in, maybe I'll give it a try and let you know what happens?

Ok, Alfa twinspark head, 16mm spark plug, bottom end went at least two years ago, insurance ran out in 2013 so it's been a while since anyone touched plugs.

Mice have been nesting in it.

Came out fine, driver was set at 150Nm, rattled away for a bit, based on past experience, it felt like it took about 100Nm to get the plug to shift, maybe a little less.

Not saying the second or third try wouldn't
bbreak it though...

 

[Eklipze3k]

lots of sound advice here... but just to tack on the end here, don't put your new spark plugs in super tight lol

I read some sound advice on here which stuck with me - tighten by hand, then 1/4 turn with a socket. Seems to have worked so far!

 

[jackwhoo]

I read some sound advice on here which stuck with me - tighten by hand, then 1/4 turn with a socket. Seems to have worked so far!

Hand tight then so many degrees more, as Indicated on plug box, is Only with new plugs that have a crush washer that hasn't been used before.
If reinstalling plugs that have previously been fitted use a torque wrench set correctly.

 

[CasLad]

Changed the spark plugs over the last two days. That Plusgas is good stuff! Couldn't have done the job without it, and it came in very useful for other service jobs that I did at the same time.
Thanks again,
Andrew