Spark plug change

[Emil]

I just trust my knowledge and experience. 

[Rooted]

Has this hot aluminium head you mention got aluminum spark plug seating/threads?

[ronime]

8 hours ago, Wino said:

Wrong. Everything gets bigger, the spark plug hole more so.

 

That has always been my understanding. A bit of heat to expand a nut around a bolt or a brake caliper around a bleed nipple has got me out of bother a few times.

[ronime]

8 hours ago, Emil said:

Let's agree we disagree. 

 

Agreed!

 

Always interesting to read your posts, Emil. Don't let us put you off.

Edited 6 September, 2017 by ronime

[Vitas]

I managed to change my plugs yesterday just used generous helpings of WD-40 and some needle nosed pliers.

 

here's how mine looked 

bit of wet fouling on 2 of the 3 cylinders. Nothing too serious I don't think

[beezera10]

Dunno what Emil is on about.  When the engine is hot, both the spark plug hole and spark plug will expand together.  If you remove a hot spark plug from a hot engine, then put a cold spark plug in, the cold spark plug will be a slightly looser fit - although not really enough to strip threads.  Probably a good idea would be to put the cold plug in finger tight and allow the temp between the engine and spark plug to equalise before nipping it up.

[Emil]

I just received spark plugs for my other car. And, I'm going to let it stand over night before I change the plugs. Just to be sure engine is stone cold. 

Edited 4 July, 2018 by Emil

[Breezy_Pete]

That's a 'health and safety' warning so you don't burn your little fingertips...

[Emil]

Might be. Still spark plug chage for cold engine. Can't go wrong. 

[Rooted]

'Some'  loosen when warmish, remove when cold and then put in the new ones.

[beezera10]

If you find your plugs are pretty solid when cold, just loosen them slightly when engine is warm.  Once slightly loose, a drop of WD40 will work its way into the threads.  I then gently retighten and loosen a few times until the threads start to free up.  When the plugs are all out, I put a new plug in each cylinder with a drop of WD40 and make sure they screw in easily before cleaning the threads and nipping them up.  Never had any problems with cars or motorcycles.

 

Can be a bit worrying when loosening really tight plugs, but following these steps will help.  After all, it doesn't matter how tight they are, they have to come out one way or another.

[Emil]

I always use torque wrench. Never too tight this way. 

[beezera10]

As someone said before, I use knowledge and experience.  I've never used a torque wrench for spark plugs, only for engine components and some parts of the suspension.

[Emil]

I guess you haven't change plugs for Ford then. Nipping them is too much. 15Nm isn't much but enough. 

[beezera10]

Yup, Fords too.

[Emil]

http://www.fordproblems.com/trends/spark-plug-ejection/

[beezera10]

Quality US company 

[Skoda-NDB]

Same thread from Up forum - with guide.

 

https://www.upownersclub.co.uk/forum/18-general-technical/9299-how-remove-ignition-coil-units-pics.html#/topics/9299?page=1

 

Picture of factory tools - if the zip-tie solution seem too sketchy

https://images.app.goo.gl/NHMTmd57FTB69c8v9

[Wurzell]

Hi 👋 when I changed our plugs while servicing I found the rubber boots where rather stubborn so I followed some previous advice and pulled the boots stretching them and then holding at a constant pressure for about a minute and it popped off and worked for all 3 when refitting I too lightly smeared the ceramic part of the plug with dielectric grease which I already had.😃

[A01]

Hi everyone,

 

I will be changing plugs soon, thank you for this thread and the link to the Up! thread.

 

My suggestion is instead of using dielectric grease  is to use talcum powder.  I had a vauxhall whose plug boots came covered in a fine white dust it might be a better idea. My concern with the grease is the plugs get very hot and it might become like a burnt glue. 

 

An engine spark plug will be up to 800°C 

and silicone grease has a working temp up to 200°C

[Eltezz]

14 hours ago, A01 said:

An engine spark plug will be up to 800°C 

and silicone grease has a working temp up to 200°C

 

Only the spark plug tip will (possibly) get to 800°C . The threaded part in the head will be closer to the water jacket temperature, so much cooler than 200°C for the silicone grease...

[A01]

I think what I might do is do one new plug with silicone grease, one with talcum powder, and one with nothing, and I'll see what it's like next year when I change/check them again.

 

Also wanted to say the reason the boots stick is because the plug ceramic is smooth - no ribs, so more surface area for contact with the rubber, silly design.

 

Also although you can buy a replacement boot £12.50 without the coil, it might be better to spend that extra £32 and get a coil for £45 then you have a spare new coil that only cost you £32 to use as a fault finder if one of your coils goes bad in the future.  If you have a bad coil simply put the boot from the bad coil on your new coil.

 

Edited 15 January, 2020 by A01

[Emil]

May not be stuck at all after one year. But why would you take them off after one year? 

[freemansteve]

If I  was worried that the rubber boots might stick over time (I don't care at all, BTW), then taking them off and on again, & cleaning them and the plug shafts, once a year may make them less prone to sticking. 

 

I was surprised to see mention of copper grease for plugs! Given high voltages, I would assume it could provide a possible path of conductance! Silicon grease would be better, but I have no idea how long it would stay effective for, or what the breakdown products would be as it degrades - it may become stickier...

 

[A01]

Would be interesting to hear how many of the people commenting have changed their citigo plugs themselves? freemansteve, emil, ronime?

 

To answer that earlier question in the thread,  the rubber pipe on the airbox is a pushfit. Use a flat screwdriver to push it off.

 

There are different coils on citigo -skoda told me there are 3 types-  there is obviously the type in the picture on page 1 here which I think is Eldora.  Mine is Beru 04C 905 110 D  if you google that you should find the type with the ridged boot. (incase the link here is not working in the future) 

https://www.winparts.co.uk/engine-parts-accessories/ignition/ignition-coil/c612/ignition-coil-0-040-102-067-beru/p575356.html 

Pretty cheap too if only they had them in stock.. £24 !!

 

It's no use spraying silicone grease to aid pulling the boot out as the boots stick to the plug ceramic inside. It's not sticking to the aluminium "plug well". 

 

I have 45K miles / 72,000 km  I bought the car I think around 20,000miles, 2.5 years ago.  

 

The other day on a frosty morning it failed for the first time to start. After a bit of coaxing it did start. For the remainder of the week it there were no issues with starting again.  I decided to check and change the plugs on the weekend.  

 

I started out today on a cold engine to remove plug No.1 it was stuck like hell. I gripped the rubber boot under the coil with my finger/thumb and used my other hand to aid in the lifting.  It did pop off after about 10 minutes.  DO NOT use pliers to grip the boot it will rip apart.

 

I could see inside the boot small white globes of silica and the ceramic of the plug was sticky.  I wiped the old plug clean, reinserted it into the boot pulled it out again each time I did this, it came out sticky, I repeated this until it no longer came out sticky.  each time pulling it out the plug was gripped hard and fast inside the boot and required a lot of strength to pull it back out (and this was with it off the car!) .  Once it was clean it was only slightly easier to pull it back out.  I coated the inside of the boot with the aid of the old plug with talcum powder. Slips and slides now with ease, so much so, that the spring inside the boot was now pushing it out itself.

 

I moved on to plug 2 and this was even worse to get the coil off, it was stretching the boot so much I was concerned.

 

I considered making a tool to slide down the outside of the boot to locate under the bottom edge of the boot and then I could pull it up from underneath.  The plug ceramic diameter is 10mm so I decided the tool would be thin enough to go down the well but thick enough to provide strength.  I decided I would get a strip of metal about 12mm wide bend it 90° (in) and  bend it again towards the top about 20° to go around the coil and then bend again out wards to use as a handle to pull on.   Drill a 10mm hole at what will be your lower end. Then cut through the centre of the hole, file it smooth. with luck this could work,  if not it might be a case of having a smaller thinner 5mm wide version without a full half circle but maybe only a 5mm square lip at the  bottom to locate under the boot.

 

I put the new plug in No.1 and secured again all coils. Warmed up the engine.  Tried again, No.1 came off easy with the talc. No.2 was still stuck, so I redid all and warmed the engine some more.  This time No.2 was still stuck, but came off within 2 minutes with a lot of force applied.   No. 3 also came off with a lot of force quite quickly.  - tip of the day is to have engine warm and plugs hot. once the plugs are hot there is no need to make the whole engine hot.

 

Again No.2 and No.3 had silica globules inside. and again I did my best to clean them until no more sticky was on the plug.  Again they were very difficult to put in and remove until I was finished cleaning and applied the talcum powder.  Replaced the last two plugs and reassembled everything.  Used standard plug tightening technique. Finger tight, then up to a 1/4 turn and no more.

 

All three plugs were worn out I have not measured their gaps yet but I estimate them to be 1.3 - 1.5mm (should be 1.0mm) !!

 

My conclusions:

I have no doubt, given how hard I had to pull these apart in my hands, refitting without a lubricant even 10 minutes later would have meant having to pull hard again to make it pop off  pulling hard and stretching these boots is not doing them any good.  So I decided not to have a control with nothing.

 

It is as I suspected, silicone grease boils at 200°C  the sparkplug tip operates at 500° - 800°C the end of the plug is all metal whatever temp is inside the cylinder the heat will easily migrate to the outside of the plug in the well and will also heat up the ceramic similarly.  You put silicone grease on and 4 years later when you are changing your plugs it will hinder rather than help because it will be a sticky mess. So I did not want to have one plug with that stuff.

 

Only attempt this on a warm to hot engine.  

 

Use talcum powder as your lubricant. 

 

I am considering removing these plugs again in the summer when the weather is nicer, to confirm that talcum powder is the best solution here.  I reckon mine will now come off easily even on a cold engine.  

 

ALSO while you're doing this you might as well change your air filter. Need a T20 (torx) screwdriver/bit to get the cover off.

 

Edited 19 January, 2020 by A01