Modern spark plug advice please

[Leveret]

I have just noticed the advice in Mrs L's Peugeot 2008 1.2 puretech Service Schedule to change her 36k miles 6yr old plugs at 30k/4yrs. Presumably the 'original equipment' is ancient soft copper alloy. Is plug technology and advice still in the plug-fouling leaded petrol 20th century? A quick search on just one site reveals a bewildering choice ranging from NGK 408773530 £4.29 up to Bosch 408994660 at £12.34 per plug which, if iridium, are apparently good for 100,000 miles and ?umpteen years. So, as it does only 6k miles p.a., do I buy cheapos and inspect/reset them every 30k, or fit pricy ones and leave them to weld themselves into the head over time? Looks as though there's an opportunity for unscrupulous garages to fleece punters by frequently fitting iridiums as per the manufacturer's 4yr advice and, ahem, recycling the old ones. Anyway, it would be nice to have some up to date clarity and advice for best VFM for mundane diy'ers like me.

[TomTheTyke]

If it’s a car I intend to keep, and am servicing it myself anyway, and it’s not under warranty….

I’d still be changing the plugs every 4 years, so I can check their condition, that there’s no oil getting down there etc. Not exactly a time consuming or expensive job.

[Watcher of the skies]

It's an old Peugeot. If it runs ok then leave them alone, otherwise the NGKs will be fine.

[finlo]

A pure tech 1.2 engine wont outlast a set of plugs!

[Smint]

As with many things, a little and often works out well enough.
Half decent NGK plugs replaced every couple of years the chances of one being seized in the head minimal, costs a fraction of sorting out a seized then snapped off plug body.

[Leveret]

finlo said:

A pure tech 1.2 engine wont outlast a set of plugs!

Nonsense! Might have been true 8yrs ago with the early pre 2019 crumbly DAYCO belts, especially if anointed with cheap non-spec oil, which effectively ruined the reputation of this excellent engine. There are now literally millions with fit for purpose belts (made with better material from Gates & Conti) happily clocking up the miles all over the globe. AFAIK only the hybrids now have chains.

[Om]

I have become conditioned to long service life spark plugs but I was surprised to see for my Fabia 1.2 (3cyl) that the plugs were recommended for replacement every 24mth/20k miles.

Until I took them out to inspect them. They had visibly degraded in the last 2yrs to the point the gap was visibly wider than on a new set.

I now swap them out every other service (20k miles). I only need 3 and for Bosch plugs that comes to about £14 so its not worth worrying about.

[Clad-Hach]

I think the last time I took a sparkplug out to check it was my lawn mower, the cars just get done at their services.

Yes I should take more interest in them but taking six out my Cayman isn't a simple job without a ramp to help.

[finlo]

Leveret said:

finlo said:

A pure tech 1.2 engine wont outlast a set of plugs!

Nonsense! Might have been true 8yrs ago with the early pre 2019 crumbly DAYCO belts, especially if anointed with cheap non-spec oil, which effectively ruined the reputation of this excellent engine. There are now literally millions with fit for purpose belts (made with better material from Gates & Conti) happily clocking up the miles all over the globe. AFAIK only the hybrids now have chains.

OP states it's a 2008 model.

[AgentZ]

finlo said:

OP states it's a 2008 model.

2008 is the car model, not the model year! OP states plugs are 36k, 6 years old as I read it. So a 2019/20 model year.