Spark plug replacement

[garethpaul]

2015 Auris, due its 6th service in March. According to the service book, it says spark plug replacement at 60,000 miles.

This says 54,000 miles. https://www.toyota-tech.eu/MS/PDFS/67ad3b19c71643719143f68802b7310a.pdf

I don't see that either specify a timeframe as an alternative (i.e. whichever is sooner).

Question is, my car has only done 39,000 miles, should I need to change the plugs or not? On inspection last year, (approx 2000 miles ago), they looked in good condition.

 

[FROSTYBALLS]

The pdf you linked shows the European service schedules (ie service intervals 1 year/15,000km/9,000 miles), which are different to the UK service schedules (1 year or 10,000 miles). Also note 9 on the pdf states 'it is possible to replace every 100,000km (60,000 miles)'.

Usually in the UK spark plugs are due for replacement at 6 years/60,000 miles, whichever occurs first - similar to coolant which for the first coolant change is 10 years/100,000 miles.

Your choice though.

[garethpaul]

Thanks for your reply.

I get what you are saying, and may just replace them for the sake of £30.

However, where are you getting the 6 years from? As I see no mention of a timeframe.

My UK spec service booklet doesn't mention it 🤔

 

[TonyHSD]

60k miles reasonable time for change, even though these can last well over 80k or more then 100k miles. I did mine first time at 80k as I was thinking they are ok for more miles but then double checked the book and realised I am late by 20k miles, the plugs were in good shape, however I will not skip changing them again. Every 60k miles, no need before that for sure. 

[furtula]

On my old 2004 mazda, i had them changed at 100k, and they were fine, it was the recommended interval, also Iridium tipped, i don't remember which brand.

[Mooly]

I replaced mine at 60k (9 years old) and was pleasantly surprised at the excellent visual condition when they were removed. Also amazed how easily they came out.

One thing I would say is to get the correct and up to date recommended plugs from Toyota rather than rely on a supposed equivalent. For my Auris Toyota had changed the heat range of the plugs and this was not reflected in other brands on offer at the time. Even worse, some were a heat range the other way from the original fitment and so now two 'heat ranges' in error from the latest official recommend.   

[Parts-King]

1 hour ago, garethpaul said:

 

However, where are you getting the 6 years from? As I see no mention of a timeframe.

Manufacturers quote time/mileage in order to be more specific for low and high milers, for instance, servicing is every 1 year/10K miles WHICH EVER IS THE SOONER, Air filter every 4 years/40K etc. Plugs would normally be 6 years/60K  WHICH EVER IS THE SOONER

[AisinW]

Just check mine today at 120k km or 70k miles. It looks good although some sticky oil residue on the tread.  I put them back. The Denso Iridium SC20HR11 or SC16HR11 is rated for 120k miles by Denso. Toyota post 60k miles in Europe and 120k miles in USA for 2ZR-FXE engines. It is probably from the facts that sometimes in Prius 3rd. Gen, this plug internally fail before reaching 120k miles.  It does not harm to change it early or just open, clean the tread with brake cleaner, and install them back to avoid siezing at 120k miles. 

My 2006 Prous has 120k miles interval on sparkplugs and at 120k miles they were still really good although it burns oil 0.25L every 5000 k miles oil change interval. 

[Wooster]

Just a thought about cleaning Iridium tip spark plugs.  Don't use a wire brush or any other abrasive.  The Iridium is plated on and very, very thin.   As it's about £3000 an ounce, you can understand why the tip isn't solid Iridium!

[AisinW]

I do not touch the tips, just the tread/screw tread.  It is coated by carbon and oil/fuel residue.  Most modern sparkplugs is nickle plated and never need antisieze but sometime the plugs are stuck from sludge, not from corrosion.  60k miles is a good time to check brakes, slider pins, pad wear, bushings, etc.  I did it just because I am curious why the sparkplugs interval is 2x than in the USA. 

[TonyHSD]

Now thieves if read that about Iridium will start walking around with spark plug tools and still peoples plugs for money 🤫😅, I usually do let the engine running for 5min before going to undo them, noticed that if the engine block is too cold or too hot they are difficult to turn but if the engine has sort of room temperature like they do easily. 

[Cyker]

Thankfully the tip has so little Iridium it'd be far too much work so there's no danger of that! Otherwise they'd be trying to nick the gold plating off USB cables too  

[roks]

Its worry as it is about the CAT thieves, now we have to watch out for sparkplugs thieves too?😟

[Cyker]

Nah, if it was really an issue Halfords would have armed guards at the door!  Think about it - It'd be much easier to nick them from a shelf than from a car!

Anyway, the amount of Iridium on a spark plug is so small you'd need thousands of them to make even a grain of sand's worth of it and spark plugs aren't something you can just quickly rip out of a car. Instead they'd be robbing motorfactors left, right and centre if there was any money in it. It has a higher melting point than the entire spark plug and is one of the hardest metals in the periodic table. I'm not even sure how you could recover it without spending more money than it's worth.

No thief is going to that much effort when a catalyst is so much easier and quicker, and even that seems to be dying down again... Haven't heard any reports of it lately... Then again that might just be the news moving on to other things.

 

[AisinW]

Folks, Iridium sparkplugs indeed revolutionise the auto industry, especially if we have v6 transverse engines like in Lexus RX.  It is a big job removing the intake manifold to reach the back 3 cyl.  120-150k miles interval on these plugs really helps ownership cost. 

I only use Denso or NGK for japanese car. I remember the previous owner of my Nissan Altima used double platinum Autolite tips. One of the platinum electrode is missing, most likely fall to the cylinder one. The same cylinder that consume engine oil, from the spark plugs reading. 

Autolite is for lawnmowers not cars. 

[roks]

Thanks for the assurance @Cyker 😃

Mine were changed by the last owner with NGK just over a year ago, when I took them off, one was very tight, one was very loose.  They looked ok so I just put them back in torqued them down evenly to 25Nm.

[AisinW]

NGK and DENSO are very close in term of laser welding quality,unlike Autolite. Both have 2 types of Iridium. Iridium (120k miles) and Iridium TT 30-60k miles.