Seized spark plug
DaveC
I changed (or attempted to change) the plugs for the first time since owning
it (about 40K of my miles). Two of the 4 plugs came out fine; #1 and #2 won't
come out.
I turned them as much as I dared -- about 3/4 turn on #1, maybe a little more
on #2. Then they got tighter.
I took the car for a 1/2 hour drive which thoroughly warmed it up. The 2
plugs didn't seem any looser.
So, what are my options?
In the dim corners of my memory I seem to remember a suggestion to loosen the
plugs just a little and squirt some auto trans fluid around the base of the
plugs (they're each in a well in the center of the valve cover) with the
design that it will seep around the threads and soften some of the carbon
deposits on the lower end of the threads.
(Yeah, I know: anti-seize compound when installing new plugs. That was my
intention...)
Thanks,
--
DaveC
m...@bogusdomain.net
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Fat Moe
than the other until I finally got them out. If you have the time it
wouldn't hurt to let them soak with a good penetratingly oil but I'd go
easy on that since it will all go down into the cylinder when the plugs
come out. It's a good idea to loosen plugs and then blow compressed
air to remove the build up before taking the plug out all the way,
cleans the seat without blowing the "junk" into the cylinder. Hope it
works for you. Worst case is the treads from the aluminum head come out
with the plugs but this one sounds like it is carbon on the end and
working the plugs one way than the other till you have them out ought to
work.
Good luck with it.
twisted
Warm is fine/recommended, not hot! It will rip the threads right out
of the head.
DaveC
> I did this with the head pipe bolts on my Crapillac and they finally
> yielded.
Thanks.
HLS
"DaveC" <m...@bogusdomain.net> wrote in message
news:0001HW.C66CEB37...@news.sf.sbcglobal.net...
>> I'd give it a dose of PB Blaster every day for a week then try again.
>> I did this with the head pipe bolts on my Crapillac and they finally
>> yielded.
Ive had to remove plugs with fouled threads a number of times. Patience
helps, aided with a shot of penetrating spray and gently turning the plugs
back and forth until they release.
Never try to manhandle them out, and especially not out of a hot engine.
DaveC
> helps, aided with a shot of penetrating spray and gently turning the plugs
> back and forth until they release.
>
> Never try to manhandle them out, and especially not out of a hot engine.
I got #2 plug out. It was not carbon build-up on the threads; the threads of
the plug were flattened, like they were turned down a little on a lathe. Hard
to describe how much -- 20 to 30 percent? Otherwise the plug was very clean.
I used a tap to clean up this spark plug hole -- a mistake I now realize. A
tap is NOT a chaser. If/when I get #1 plug out I'll use a chaser.
The last plug is VERY stubborn. I can turn it a total of about 3/4 turn, then
it binds up. I've sprayed PB Blaster down in the plug well (which is centered
in the valve cover) several times today. I'm going to try turning it again in
the morning.
Do I just keep trying (turning back and forth 3/4 turn) even if there is no
change in the resistance? Do I eventually use the breaker bar and force it
out? Then look into installing an insert?
Speaking of which, can inserts be done in-place? Or must the head be removed?
Thanks,
DaveC
What brand / type are recommended for this application?
Is it necessary to remove the head?
ben91932
> I turned them as much as I dared -- about 3/4 turn on #1, maybe a little more
> on #2. Then they got tighter.
Loosen... run motor.
Tighten... run motor
repeat
HTH
ben
john
"forever", especially in aluminum heads. At least remove/reinstall
them 3 years/30K miles, even with newer plugs with once-use antiseize
coatings. A dab of antiseize at least 3 threads away from the tip.
Find 1oz tubes at your local parts stores.
Thread repair: for these high-stress situations, use Time-sert, I
wouldn't use helicoil for plug or head bolt threads. http://www.time-sert.com/
A spark plug thread chaser, $4.99:
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=97277
Raymond Sirois
obviously impaired state, wrote:
>
>The last plug is VERY stubborn. I can turn it a total of about 3/4 turn, then
>it binds up. I've sprayed PB Blaster down in the plug well (which is centered
>in the valve cover) several times today. I'm going to try turning it again in
>the morning.
>
>Do I just keep trying (turning back and forth 3/4 turn) even if there is no
>change in the resistance? Do I eventually use the breaker bar and force it
>out? Then look into installing an insert?
>
>Speaking of which, can inserts be done in-place? Or must the head be removed?
>
>Thanks,
If the last plug is the same as the damaged one you removed,
you have little choice but to strong-arm the plug out. Everyone will
tell you that you should remove the head in order to properly install
the insert. I've done it in place, taking precautions to prevent the
metal chips from entering the combustion chamber. Granted, this was
on an aluminum head (similar to yours, I'm sure), and I could
literally crush and grind the chips between my fingers. Figured if
they were THAT soft and brittle, then the one or two I might have
missed wouldn't do TOO much damage.
--
Ray Sirois
SysOp: The Lost Chord BBS
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