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Hi all.

2 of the 3 bolts holding the coil packs in place have siezed on my car.

I can't loosen them and i have partially mangled the heads of the bolts trying to undo them.

Any advice on how I get them out?

luckly I am able to remove the 3rd bolt holding the bracket to the block, so in theory I could remove the whole cover first then try to remove the coil bracket from the cover with the cover off the engine...

that's a lot of work for some stupid bolts.

Try it again, but carefully and with a really good-quality spanner. Sometimes the closer fit from a good quality piece can save your ass in a sitch like this.

Thanks,

Will try.

found this:
http://www.diyfaq.org.uk/fasteners/fastener.html


wd-40ing it tonight.
then will try tightening before loosening.

You have to be ver careful with any bolts into the head, block or gearbox since the steel bolts react with the alloy and sieze up. The easiest way around this is to, as you already said, is to apply WD40 or similar, tighten the nut then lossen it, or tap it a few times with a hammer. Either way, be gentle as it is very easy to strip the head off the bolt or worse, strip the thread in the alloy!

Also be wary that sometimes for stupid reasons dodgey mechanics will apply loctite or similar to bolts in the alloy which will severaly compound your problem! (Especially annoying whne the bolt serves no real \"critical\" purpose to the running of the motor)

and when it does come out, put some anti-sieze on the thread so nothing like this will ever happen again..

like some one said give it a bit of a tap with a hammer. but use a punch or metal rod (a lump of brass or copper is better if your worried about dmg to bolt head) and hit down on the bolt head. this can sometimes even make it easier to undo loctited threads.

basically the down ward shock compresses and rust, grit or loctite thats in the thread then it can be alot easier for the bolt to spin through the thread. just be carefull not to mangle the head of the bolt when you do it. use a punch thats as big as you can get on the bolt head and give it a good hit. (your not trying to drive the bolt through the block like a nail, but you dont want to just drop the hammer on it)

sorry if this seems like trivial info to you, not sure of your mech knowledge but hey, maybe someone else will read it and learn some thing. so not meaning to insult your knowledgability

If you tried it cold, try it hot. Alloy and steel have different coefficients of thermal expansion (alloy expands more per degree).

Cheers,
Alf

If you have already rounded the corners of the bolt head you could try and find someone with a set of Metrench spanners or sockets. They grip the flats of the head not the corners like conventional spanners/sockets.

If they are REALLY REALLY BAD then drill a hole in the centre and use an Ezy Out to remove them or use a Dremel to grind the head of the bolt away remove the coils then cut a slot in bolt shaft and use screw driver to remove it.

Obviously the Ezy Out and Dremel are drastic measures to be used only if all the advice above fails.

if the bolt head is still in good condition, just spray it with maxisolve or wd then put your ring spanner or socket on, dont use a open ender. once in position then apply a breaker bar. try the longest breaker you can find and use a friend to hold the socket-spanner in postion while you heave. this should work. if you strip the head then it looks like drastic measure time as kam said use the easy out.

KAM wrote:Obviously the Ezy Out and Dremel are drastic measures to be used only if all the advice above fails.

The engine will have to come out before you'll be able to do it too.

Insurgence wrote:
luckly I am able to remove the 3rd bolt holding the bracket to the block, so in theory I could remove the whole cover first then try to remove the coil bracket from the cover with the cover off the engine...

that's a lot of work for some stupid bolts.

JBT I did say "drastic measures"

KAM wrote:JBT I did say "drastic measures"

Aaaah, I missed that bit about getting the third (I assume lowest) bolt out.

ok.

i've tried:

-tapping/hammering bolt to loosen it
-vice-grip pliars to turn bolt
-hacksawing the bolt to turn it into a screw (ie cut down centre of bolt head)
-good quality spanner didnt work cos i already mangled the heads.
-hot/cold thing didnt seem to work


I dont think i can get the right leaverage to turn the bolt the way it's located.

i want to remove the cover then see if the bolts come off easier. i think i can use a screwdriver to get it out ok once the cover is removed

are there any caveats in removing the cover?
-do i need to put new silicone on if i'm not replacing the gasket?
-i have to get the 100,000 service done soon (asap) so can i just do the cover removal + install then let them change the seal etc.?
i'll be following:
http://www.miata.net/garage/valvecover/index.html
btw i'm pretty noobie so start at the start

Insurgence wrote:are there any caveats in removing the cover?
-do i need to put new silicone on if i'm not replacing the gasket?
-i have to get the 100,000 service done soon (asap) so can i just do the cover removal + install then let them change the seal etc.?
i'll be following:
http://www.miata.net/garage/valvecover/index.html
btw i'm pretty noobie so start at the start

Caveats: try not to break the cam cover "O" ring gasket. Lift the cam cover off carefully.

Put a dab of sealant in the 6 places as recommended in that link you have, even if you re-use the old gasket.

thanks JBT and everyone!

will try on weekend!