500 Spark Plugs

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500 Spark Plugs

SteveG2021

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Well I bought a 2017 500 sport in a beautiful metallic blue
Bit different from my 2.00 Diesel Berlingo of 13 years
Incredibly fuel efficient 190 miles on £23

Excellent condition 28000 miles
quick local garage service
Last week I thought I'd change the plugs probably never had new ones
Very difficult to access with my conventional sockets
So ordered a Proper plug spanner
when it arrives I'll give it another go
Last time I changed a spark plug was 15+ years ago on my ZX9
 
Whichever plugs you opt for, double check the gap before fitting. I had one iridium plug that was far too small a gap, possibly damaged in transit.

Be very careful if checking the gap on an Iridium plug, the iridium electrode is extremely brittle and if it breaks in service, it will almost certainly destroy the engine.

Never attempt to check the gap with a ball type tool (some say never use any kind of tool to check it), and never attempt to adjust it; if the gap isn't correct, put the plug in the bin.

Be aware the gap on the NGK iridiums is preset to 0.8mm (the OEM plug spec is 1.0mm). Don't attempt to adjust them; the engine will be just fine with this, and it will put less stress on the coil packs, too.


Am I the only one who worries about leaving plugs in for longer?

It's a reasonable concern; I'd never fit any plug without putting heat resisting anti seize on the threads, especially so with a long life one. I've never had any problem removing plugs I've fitted myself, though I have experienced issues removing factory installed ones.

If it really bothers you, there's nothing to stop you removing and replacing them every couple of years.
 
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When I was a lad, it was more or less mandatory to remove the plugs every few months at least, just to have a butchers.

I still can't leave them too long, although these days with modern engine management systems and no points/condensers to norks things up, there's not much to do except put them back again.

In my experience, the flashy plugs work out more or less the same £/mile as regular plugs but I can't say I've noticed much difference, if any in performance/starting/fouling etc.

Iridium definitely last longer, so if you have difficulty getting into the engine to have a look every so often, then they're a better bet than regular iron plugs.

Use the correct torques to do the plugs up... although back in the day I used to be able to get the torque almost spot on, just using my bare hands and muscle memory... :D


Ralf S.
 
My measure is if you can unscrew them with a short (5-6 in) T-bar plug socket, then torque was ok.

When you put it back in (ideally in a cold or not too hot engine) use one hand only to tighten.
 
Some very good advice being given above and I'm in broad agreement with it all - does that sound pretentious, sorry. In particular I'd strongly advise against messing about with the gap on longlife plugs with thin wire centre electrodes which are very brittle and can be easily damaged. If you need to adjust any plugs then buy yourself a tool which grips the outer electrode only, levering against the centre electrode is bad practice, although I've done it myself in the past without any obvious problems on "conventional" old type plugs.

Until very recently I was firmly in JRK's camp which is to say I always applied copa slip to plugs going into cast iron heads and Alu slip for aly heads and tightened using "Jock's five fingered torque wrench". I've done plugs this way for as long as I can remember and never had a problem but there is an increasing body of opinion that now, with anti corrosion plating on plug threads, anti seize is no longer needed and in fact may be detrimental. See this: https://ngksparkplugs.com/en/resources/5-things-you-should-know-about-spark-plugs. I've been asking around the local garages and they are all installing them "dry" now and most are using torque wrenches - which, of course, become irrelevant the moment you put anti seize anywhere near the threads..

I do agree with Ralf S who says he regularly removes checks and reinstalls them because with modern plugs being untouched for maybe 5 years or more, although thread corrosion may be much less of a problem, carbon build up on the last couple of threads on the combustion chamber end of the plug can cause thread damage when the plug is eventually removed. There's also the problem of coil packs bonding to the plug insulator. My Ibiza is apparently prone to this and the lads at AVW tell me it can be so bad that the coil is destroyed during removal. If the coils are removed once a year and given a light smear of silicon grease - or similar - around where their seals go over the plug ceramic then this problem virtually disappears. Good idea to use some silicone grease on our FIRE engine HT lead plug caps too as they can be a pain to remove too.
 
I've done plugs this way for as long as I can remember

Don't be too quick to abandon the old ways; just be mindful of cats and lambda sensors, which can easily be poisoned.

I've had to deal with too many seized plugs over the years to assemble them dry, particularly if I know it could be five years or more before they're coming out again.
 
Don't be too quick to abandon the old ways; just be mindful of cats and lambda sensors, which can easily be poisoned.

I've had to deal with too many seized plugs over the years to assemble them dry, particularly if I know it could be five years or more before they're coming out again.
Aye, "abandoning the old ways"? I have to say that although everything is pointing towards me doing this the "new way" I'm still not 100% convinced and I suspect I'll still be, carefully, slaistering a bit of copaslip/alumslip on most of the ancient "family fleet" or my old machines and bikes because it just feels "right". I don't use a torque wrench when doing this as I've been doing it so long I know just how tight "tight" should feel and I feel more confident doing this than "guessing" at a torque figure. Point taken about the sensitivity of O2 sensors and cats. In fact I'm quite obsessive about this even to the extent that I will only use a sealant on stuff like cam covers, water pumps etc which is approved cat friendly.

My Ibiza and my older boy's Kia (which is a diesel - the Punto is his 2nd car) are the only modern cars in the fleet and the Kia is still under the extended warranty (7 years!). He hasn't had to claim for anything yet and I can't wait to see, if he ever has to, whether they try to wriggle out of it. I believe that what's covered is a steadily reducing list as it's age increases? Anyway I mention this because the Ibiza was looked after by the main dealer until I did it's first service at 4 years old. I've just completed her service for this year - year 5 - and I see they recommend renewing the plugs. Although now 5 years old she's only done just over the 21,000 miles since new so I'm guessing the plugs will still be good for many miles yet so I've decided I'm going to let the lads at AVW remove them and advise me regarding renewal. As they are doing this all the time I'm guessing they are far more likely to be successful at avoiding coil damage than me. - I believe there's a "special" extraction tool which helps too. From then on I'll remove them every year for visual inspection and to smear a little silicon grease in relevant places. I'm also going to get the cam belt done (which is recommended at 5 years) and an aircon recharge. Lastly, I'm swithering over getting the coolant changed. I wouldn't attempt this myself as the car has two coolant circuits, one through the turbo involving an electric pump which can continue to run after engine stop which seems a good idea to me regarding turbo longevity but adds considerable complexity. Talking about complexity the main cooling system is in two parts as well. One circulates through the head and heater which promotes rapid warm up and heater temperature with the block heating more slowly. Two thermostats are involved to achieve this - Oh dear! I wouldn't try changing the coolant myself as I've heard that air locks are common and difficult to clear and you need pressurized equipment to have any chance of completing it successfully. I believe the dealer claims the original factory fill coolant is good for 10 years? I think I'll go by what AVW recommend.
 
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