Modern spark plug advice please
Discussion
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.
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.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.
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.
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.Correct! Admittedly looks ambiguous but the 2008 only appeared in 2013.
A further confusion is the length of the thread. On putting in the reg no. BT69ETX into numerous parts outfits I am offered a bewildering variety of plugs with thread length varying from 25.5mm to 28mm. Why? I seem to remember reading somewhere that the 130hp engine (which it is) has the 28mm length, but I'm unsure. Anyway, I don't know how they sit in the head but I sure don't want to knock a hole into the top of the pistons! In 50yrs of spark plug changes I have never known such confusion - there is nothing in all the original documentation of what was a brand new car in 2019 to say what plugs should be used. And if they are all iridium or platinum renowned for long life, why change every 4yrs or at such a low mileage? Nul points to Peugeot for clarity.
A further confusion is the length of the thread. On putting in the reg no. BT69ETX into numerous parts outfits I am offered a bewildering variety of plugs with thread length varying from 25.5mm to 28mm. Why? I seem to remember reading somewhere that the 130hp engine (which it is) has the 28mm length, but I'm unsure. Anyway, I don't know how they sit in the head but I sure don't want to knock a hole into the top of the pistons! In 50yrs of spark plug changes I have never known such confusion - there is nothing in all the original documentation of what was a brand new car in 2019 to say what plugs should be used. And if they are all iridium or platinum renowned for long life, why change every 4yrs or at such a low mileage? Nul points to Peugeot for clarity.
Leveret said:
Correct! Admittedly looks ambiguous but the 2008 only appeared in 2013.
A further confusion is the length of the thread. On putting in the reg no. BT69ETX into numerous parts outfits I am offered a bewildering variety of plugs with thread length varying from 25.5mm to 28mm. Why? I seem to remember reading somewhere that the 130hp engine (which it is) has the 28mm length, but I'm unsure. Anyway, I don't know how they sit in the head but I sure don't want to knock a hole into the top of the pistons! In 50yrs of spark plug changes I have never known such confusion - there is nothing in all the original documentation of what was a brand new car in 2019 to say what plugs should be used. And if they are all iridium or platinum renowned for long life, why change every 4yrs or at such a low mileage? Nul points to Peugeot for clarity.
Yeah parts searches are often a minefield with constant changes. In your case I would be fairly confident the correct plugs would be e.g:A further confusion is the length of the thread. On putting in the reg no. BT69ETX into numerous parts outfits I am offered a bewildering variety of plugs with thread length varying from 25.5mm to 28mm. Why? I seem to remember reading somewhere that the 130hp engine (which it is) has the 28mm length, but I'm unsure. Anyway, I don't know how they sit in the head but I sure don't want to knock a hole into the top of the pistons! In 50yrs of spark plug changes I have never known such confusion - there is nothing in all the original documentation of what was a brand new car in 2019 to say what plugs should be used. And if they are all iridium or platinum renowned for long life, why change every 4yrs or at such a low mileage? Nul points to Peugeot for clarity.
NGK ILZKGR7B8G (97434). I've seen change intervals (from dealers) of 32,000/4yrs and apparently these NGK plugs require a 12-point 14mm spark plug socket too. As for long-life iridium plugs....another confusion as apparently there are standard iridium and long-life iridium!
When I did my spark plugs I just ran the new ones in on an extension by hand until they bottomed out and then nipped them up a quarter turn. Usually spark plug torque settings range from 15-25nm.
My daughter complained her 2018 C3 with a 1.2 Puretech was running rough - she thought it just "needed a set of spark plugs"
I was assuming a coil pack, but it was indeed one of the plugs. It's electrode was almost completely worn out, once changed it ran perfectly !
I was assuming a coil pack, but it was indeed one of the plugs. It's electrode was almost completely worn out, once changed it ran perfectly !
Edited by littlebasher on Monday 23 February 09:31
The electrodes do wear away due to the arc plasma vaporising a small amount of the surface each spark. They do need changed. The larger the gap the higher the amps drawn to make the jump, so the coils will be taking the hit on it's fine wire windings.
I always stick with the manufacturer reccomended ones. There's usually a selection in the handbook. I have noticed that 'better' plugs can sometimes cause issues, most notably on small engines.
Having had plugs seized in alloy heads and causing serious additional work, I would want to change them out every 3rd service to avoid that mess.
I always stick with the manufacturer reccomended ones. There's usually a selection in the handbook. I have noticed that 'better' plugs can sometimes cause issues, most notably on small engines.
Having had plugs seized in alloy heads and causing serious additional work, I would want to change them out every 3rd service to avoid that mess.
Update.....fifty pound's worth of NGK 97434 later, plus a new £7 twelve point plug spanner as my old 14mm box spanner wouldn't get enough grip...aarrgghh! Anyway, the original Bosch R6 iridiums came out easily enough, no oil or water in the depths. As you can see from the photo they look almost as good as new. With my trusty old feelers I got 29thou into the new plugs, and 31 thou into the old ones. Indeed, the central electrodes in the old ones look sturdier than the NGKs! So I shall tap them down to 29thou and reinsert them after another 30k miles when I see what the NGKs look like...if I live that long. This modern pricy iridium exchange advice every four years for a mundane runabout seems to me to be verging on an official scam. Thankfully, at 28mm thread length the NGKs are exactly the same length as the Bosch originals. I wonder what, if any, difference the 25.5mm length plugs would have made to performance.
Nice one. I bet it would have cost well over double that at the main dealer even allowing the extra cost of the 12-point socket.
I bet the car feels more responsive now. It seems these PSA Puretech engines are very sensitive about spark and need changing more often than you would think.
I bet the car feels more responsive now. It seems these PSA Puretech engines are very sensitive about spark and need changing more often than you would think.
Leveret said:
Update.....fifty pound's worth of NGK 97434 later, plus a new £7 twelve point plug spanner as my old 14mm box spanner wouldn't get enough grip...aarrgghh! Anyway, the original Bosch R6 iridiums came out easily enough, no oil or water in the depths. As you can see from the photo they look almost as good as new. With my trusty old feelers I got 29thou into the new plugs, and 31 thou into the old ones. Indeed, the central electrodes in the old ones look sturdier than the NGKs! So I shall tap them down to 29thou and reinsert them after another 30k miles when I see what the NGKs look like...if I live that long. This modern pricy iridium exchange advice every four years for a mundane runabout seems to me to be verging on an official scam. Thankfully, at 28mm thread length the NGKs are exactly the same length as the Bosch originals. I wonder what, if any, difference the 25.5mm length plugs would have made to performance.
I think the ceramic insulation looks thicker on the old ones, but you can also see material build-up on the tips of the electrode.AgentZ said:
Nice one. I bet it would have cost well over double that at the main dealer even allowing the extra cost of the 12-point socket.
Skoda dealer wanted £175 to change 4 plugs on wife's Karoq. It's on a service contract, but incredibly (to me) plugs aren't included.I refused as it's only done 12K miles / 3.5yrs, and they're on a 4yr/40K mile change interval.
Next service it'll be on a plan that does include them, although I'm half expecting them to refuse and say they should have been replaced last time.
Sheepshanks said:
Skoda dealer wanted £175 to change 4 plugs on wife's Karoq. It's on a service contract, but incredibly (to me) plugs aren't included.
I refused as it's only done 12K miles / 3.5yrs, and they're on a 4yr/40K mile change interval.
Next service it'll be on a plan that does include them, although I'm half expecting them to refuse and say they should have been replaced last time.
Pretty crazy for a set of spark plugs that takes about 15 minutes to change. I remember when I did mine (Seat Mii) almost 4 years ago the dealers wanted >£100 too and I did them for £21 using OE NGK's. I see now they have reduced the price of a spark plug change to £60-£70, still a lot but shows they seem to make up pricing as they go along.I refused as it's only done 12K miles / 3.5yrs, and they're on a 4yr/40K mile change interval.
Next service it'll be on a plan that does include them, although I'm half expecting them to refuse and say they should have been replaced last time.
AgentZ said:
Pretty crazy for a set of spark plugs that takes about 15 minutes to change. I remember when I did mine (Seat Mii) almost 4 years ago the dealers wanted >£100 too and I did them for £21 using OE NGK's. I see now they have reduced the price of a spark plug change to £60-£70, still a lot but shows they seem to make up pricing as they go along.
I think they've gone completely mad. Same place wanted a £109 for a brake fluid change. Takes about 5 mins in a garage with the car already on the lift, and I've heard too many stories of it not being done at all.Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff