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  • How to: Changing spark plugs
  • Premier Icon Saccades
    Free Member

    First time servicing a Petrol (1.4 mk3 clio) and I’m going to change the spark plugs.

    I have a STW approved Halfords 170 piece professional socket set which has a large section of what I think are spark plug sockets, so I have the tools.

    Anything I need to be particularly aware of (cost of plugs btw?), have only ever serviced diesels so slightly wary that I’ll bugger something up.

    Premier Icon jeffl
    Full Member

    Unscrewing plugs is easy. Need to ensure you don’t cross thread the new one’s when screwing them in. Some people use a length of rubber hose, others use their fingers. I think you may be able to use the spark plug socket as it has a rubber inside to grip the end of the ply loosely.

    Premier Icon scaled
    Full Member

    I managed to do it in the dark, i’m a complete imbecile with anything mechanical.

    Plugs are relatively cheap, if it’s a mk3 the HT leads should be alright for another while, but they’re an easy change as well when you get round to doing it.

    Just make sure you take note of which leads go to which cylinder when you take them off 😀

    Premier Icon richmars
    Full Member

    As above. If you can, use your fingers to re-fit them. Should just screw in easily. If not, stop.

    Premier Icon yorkshire89
    Free Member

    Do you need to set the gap with the new plugs before fitting?

    Premier Icon mrjmt
    Free Member

    Get some work done.

    Premier Icon Saccades
    Free Member

    I’m hoping they will be pre-gapped (is that a thing?).

    I don’t recall any rubber in the socket set – although I haven’t looked closely tbh.

    This engine has coil packs – do I need to change HT leads and coil packs? I mgith as well go the full hog.

    Engine is idling a bit rough, fuel economy has dropped and there isn’t a lot of power – hoping this will fix that.

    Premier Icon yorkshire89
    Free Member

    Could just be the throttle body or idle control valve needing a clean out, would give that a go before replacing leads and coilpack.

    Check all the old plugs are golden brown on the tips when they come out so you know its not a problem in one cylinder.

    Premier Icon ransos
    Free Member

    Just make sure you take note of which leads go to which cylinder when you take them off

    Do them one at a time…

    Premier Icon johndoh
    Free Member

    Check all the old plugs are golden brown on the tips when they come out so you know its not a problem in one cylinder.

    Sage words. Brings back memories of DIYing my old Mini 1275GT

    🙂

    Premier Icon finishthat
    Full Member

    Take care with coil packs and how they are connected to plugs – easy to damage on some cars – plugs are pre-gapped but if dropped or knocked can be wrong so you should check -very important to start new plug in thread by hand and to be sure it is not cross threaded – ie do it up by hand until it seats on the special crush washer – then you only do them up 3/4 turn max – there are directions on the plug boxes usually . Basically take your time – and if you have any history of ham fisted bodgery/breakage get somebody who has done it before to help.
    Do not buy the cheapest plugs you can get on auction sites as they could well be fakes – NGK website has details of fakes.
    Depending on how the coil pack/s are setup you may have no wires just a pack on each plug or a pack and wire to plug .
    Rough idle and low power could be something else – but with most modern cars the plugs get left in almost forever so unless you know they have been changed its worth doing.

    Premier Icon richmars
    Full Member

    Unless things have changed, you’ll need to set the gap.

    Premier Icon molgrips
    Free Member

    I think things have changed and they are pre-gapped.

    But check, as above.

    Premier Icon bj116
    Free Member

    Coil packs may do away with HT leads as they usually (there’s bound to be an exception) mount straight on the top of the plugs. A duff coil pack made my Mrs Peugeot run rough. After first trying new plugs, she changed it for not too many pounds and that sorted it right out.

    *Tip from Motorbike plug changing (a bi-annual event!)* I stuff the hoover pipe down over the plug before removal, to suck out all the stones/leaves/dead flies that would otherwise end up in the cylinders! 😉

    Premier Icon butcher
    Full Member

    Easiest job you can do. I think the proper plug sockets come with a rubber insert (presumably to grip the plug and lift it out?) As said, just tighten by hand. Do one at a time. Should take 5 minutes. Depending on the car, the biggest problem you might have, is getting to them. Obviously try not to drop anything into your engine while they’re out!

    Plugs are dead cheap, unless you buy the premium stuff.

    Idling a bit rough could be many things. But no harm in swapping out the cheapy serviceable parts first.

    Premier Icon toppers3933
    Free Member

    It is a super easy job but as someone up there said, do one plug/HT lead at a time. You can’t get the leads in the wrong order that way.

    Premier Icon richmars
    Full Member

    I think things have changed and they are pre-gapped.

    What?
    What’s the world coming to?
    You mean I can throw away my feeler gauges?

    Premier Icon Lady Gresley
    Free Member

    Goodness me, reminds me of the time about 15 years ago when the ex sent my son round to me to show him how to change plugs and HT leads on his old Fiesta!

    Premier Icon wobbliscott
    Full Member

    Just don’t over tighten the plug in the head – the threads can easily strip the threads in the head. Just give them a good nip and that’s all they need. Times i’ve not gapped plugs i’ve had no problems at all with the running of the car. If elements of your ignition system are marginal then you might get problems. No harm, it will expose other elements of your ignition system that might need changing.

    Premier Icon falkirk-mark
    Full Member

    I think it is a special plug spanner for that car (deffo is for the 1.2) I managed it with a thin walled socket (the plugs are down tubes on the 1.2) then took the plug out with a rubber tube pushed onto the spark plug top.

    Premier Icon tron
    Free Member

    Buy NGK plugs. They’re the best make you can get. They will be pre gapped and come with cardboard tubes on the end to stop them getting knocked. In theory you could check but in practice…

    Coil packs generally last years and mount straight onto the plug. Normally secured by a small bolt and then just pull off. The top of the plug is ribbed so the coils can take a bit of pulling off.

    The trickiest bit may be removing the old plugs if they’ve been in there for 60k. Some cars (ie Mk1 Ka) are buggers for seizing in plugs. Have a Google and see if yours is. If it is, spray plus gas down the plug holes and let it sit for a while. And take care undoing them!

    Premier Icon trail_rat
    Free Member

    The hard bit is getting genuine ngk plugs. Buy from reputable source not ebay !

    Premier Icon thisisnotaspoon
    Full Member

    Or just buy OEM plugs from a dealers parts counter. Ford ones are about half the price of some branded ones for example.

    Premier Icon Cougar
    Full Member

    Clear the holes of crap before you start removing so that nothing falls in.

    Don’t change the gap.

    Do them one at a time.

    Don’t over-tighten them; finger tight plus something like 1/8th / 1/4 turn with a wrench, RTFM.

    Premier Icon molgrips
    Free Member

    Or just buy OEM plugs from a dealers parts counter.

    Unless it’s a Toyota who charge 50% more than online.

    A tiny smear of copper grease on the threads, so they come out next time.

    Premier Icon kayla1
    Free Member

    You mean I can throw away my feeler gauges?

    No, you’ll need them for checking the ring end gap when you do the top end.

    Plugs go finger tight plus an eighth of a turn at the most 😀

    Premier Icon Saccades
    Free Member

    It’ll be proper sparks from a proper autofactors – brother used to use ngk in the tweaked metro turbo & rs2000 so that’s a no brainer.

    I’m quite good at finger tight and 1/8th – stator plates for 0.005″ tubing helps.

    Slightly worried about removing – will plus gas them a shed load and see what happens – car is 178k km, was serviced but the coil pack jumped out (spark plug really) just after, service garage took it back but I’m pretty sure they were bodged fixed as everything else they did was.

    Premier Icon integerspin
    Free Member

    No, you’ll need them for checking the ring end gap when you do the top end.
    Plugs go finger tight plus an eighth of a turn at the most

    What about points and tappets?

    Premier Icon kayla1
    Free Member

    Aye, if you like. Four strokes though, innit. Two too many strokes for me 😀

Viewing 29 posts - 1 through 29 (of 29 total)

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