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I finally got around to replacing my spark plugs on Saturday. Mileage 67000 - I said I wouldn't do it until 100K but now that the Denso recommended plugs are iridium Denso IKBH20TT rather than the original Platinum plugs and are available for £42 something a set I decided to plunge in. I also replaced the surge tank to manifold gaskets (3 off) - I bought them from RockAuto for about £19 including postage.

I've watched the video on YouTube but haven't been able to find a workshop manual type guide for this job, so I've put one together so you can print it off and keep it handy whilst doing the job.. It uses the Lexus instructions for removal of the coils (which then gives you access to the plugs), an exploded diagram of the relevant part of the intake system and some notes which might help. You have to remove the air surge tank (incidentally this is not the inlet manifold, as frequently mis-stated, here and elsewhere).

Most of the excess time for the job goes on a few frustrating things - the stupid inaccessible bolt on the back of the surge tank, the clip for the main power feed from the Battery and a couple of other things. I'm sure that if it weren't for them the job could take an hour, but as it is, allow an afternoon!

At least I have the satisfaction of having saved a wedge of money compared with dealer charges and I know the job has been dome properly.

Incidentally I wondered whilst doing the job if the surge tank had really been removed  only a couple of years ago when the fuel pressure sensor seal was replaced - or was it? I began to wonder if the dealer had just used some sort of sniffer, decided the seal was OK and done nothing. They had the car for a suspiciously short time and did a video of various safety checks too. It just felt  as if no-one had been in there for 12 years, not just two years ago. Might be my imagination!

IS250 spark plug replacement.pdf

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Thanks for taking the time and effort to put that together John. I'm sure that will come in handy to a lot of people.

I've grabbed a copy to keep in my Lexus folder on my PC.

 

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Excellent piece of work and again I will refer to this in the future, having said that... I have checked the service history ( via the 'MyLexus' app) of my car and it turns out the plugs were replaced at the 6 year point ( at 22,000 miles!) the car is now at 40,000 miles and 11 years old so even though they ( in theory should be done @ 12 years) will be due next year and  I will prob have about 45,000 done by then. So I am aware that plugs only degrade through actual use and it will irk me slightly to replace them again at less than 25,000 miles! ( when Lexus uk  recommend  60k & IIRC Lexus US 100k)

paul m.

 

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all said and done, on the other hand would you want a set of plugs in your engine for twelve years lol

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Mine were and actually they were probably perfectly OK for a good few more miles and years yet!

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Good write-up - one of the few people to do this. It was on my list but the car was written off before I got a chance. Good reason not to do it

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really that's great but wouldn't like to keep mine in that long though 😊 

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Toyota/Lexus do not seem to have a consistent policy for spark plug change intervals. My Prius service interval using iridium plugs says remove and inspect plugs at 60,000 miles. lubricate threads with anti seize compound, and refit. Change plugs at 120,000 miles or 10 years.
Now we all know plugs generally only deteriorate with use "number of sparks", and the Prius engine probably runs at higher revs than other cars Toyota/Lexus make.

John

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A thank you also from me for the guide ,I have not had to do this yet as low mileage car ,but I will use this guide .I think we should stick to the mileage figure and not time as a spark plug will not deteriorate any quicker with lower mileage I have removed these types of plugs from other vehicles at 60-65000 miles and they have looked in excellent condition .With regard to concern on if work has been carried out , as my REME trained grandad  told me many years ago  if you want a job doing properly do it yourself

Dave

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I would rather stick to time rather than mileage,just a matter of choice 

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thanks for taking the time to make this tutorial !

how long would you say the task took?

 

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Probably about 2½ hours start to finish, but as I mentioned, there are a few frustrating things - inaccessible bolts, stupid clips, buried bolts needing a slim hex drive tool - once you've done the job and are prepared for them I'm sure it could be done in an hour. But this isn't a job you're going to repeat that often!

Fundamentally you only have to disconnect/reconnect maybe a dozen clips and a couple of dozen nuts and bolts.

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My car has hit 86K miles and not had the plugs done yet so I'm lining up the parts and time to do them.

The guides and videos are excellent and the only thing I've been having a bit of trouble with was tracking down the gaskets mentioned.

By taking the part number 17176-31050 off a web photo of the packaging and searching the web I've located them for sale here https://www.onlinecarparts.co.uk/ajusa-7188927.html at £6.27 and it states 3 are required so £18.81 plus £8.45 postage so over £27 - Does this sound right or expensive for a few bits of rubber.

Also, please can anyone recommend the best place to buy the iridium plugs. Lots of choice but also lots of fake plugs about.

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I will have no hesitation in getting my plugs ( Geniune OE Denso) from this seller as there is no way I will chance for the sake of saving a few quid some Chinese fakes that may drop their earth electrodes at some point!

Ebay item No 183333810155 from seller LexusBirm. Currently £79.99 

As for the gaskets if they are still quite supple and not dry and ridged then as they are of the silicon type they should (hopefully) be reusable.

paul m.

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6 hours ago, Texas said:

I will have no hesitation in getting my plugs ( Geniune OE Denso) from this seller as there is no way I will chance for the sake of saving a few quid some Chinese fakes that may drop their earth electrodes at some point!

Ebay item No 183333810155 from seller LexusBirm. Currently £79.99 

As for the gaskets if they are still quite supple and not dry and ridged then as they are of the silicon type they should (hopefully) be reusable.

paul m.

Thanks Paul. I've heard Lexus Birmingham are good. I'll order the plugs from them.

Problem with a wait and see approach with the gasket is that if they aren't any good I'd have to delay reassembly and its my every day car so I'll pay the £27 if I have to but was surprised at the limited option to obtain the gaskets.

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LexusBirm do state on their eBay page that if you want a part then get in touch as they cannot list everything!!!

paul m.

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When I changed my plugs I bought the gaskets from My Lexus dealer. From memory they were not expensive and you are guaranteed a perfect fit.

My only problem was a broken release clip for one of the coil connections.  They do become brittle with age and break rather easily.  Not the end of the world but annoying at the same time.

All in all a very satisfying afternoon's work.

Enjoy.

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