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spark plug replacement

Discussion in 'Gen II Prius Care, Maintenance and Troubleshooting' started by TucsonPrius, Jun 17, 2006.

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  1. Jo_Vincent

    Jo_Vincent Junior Member

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    I also used the instructions found in this forum to change my spark plugs (43K miles). The instructions were very good. The treads on the plugs were very dry (4 1/2 years) and "breathed" a sigh of relief when I put some anti-sieze on the threads.
    Getting the connector off of the last coil (I think it is the number four cylinder) was a little tight but it all worked out find. I did not replace the plugs, the gap was .040 and the plugs were burning very clean.
    Some items of interest are:
    I used compressed air to blow off some dirt on top of the engine so that dirt:cool: would not fall into the cylinder when I removed the plug.
    After disconnecting the negative side of the aux battery, I made sure the hatch was not closed. I know the manual method for releasing the hatch but I don't like the idea "locking" my self out and having to crawl in through the back seat to release the hatch.
    Thanks again.
  2. V8Cobrakid

    V8Cobrakid Green Handyman

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    I'm attempting to do this now... what a pain! it's not the bolts.. or the coils.. it's the spark plugs being buried in there so far... like.. the center of the engine....
  3. V8Cobrakid

    V8Cobrakid Green Handyman

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    easy enough.. i guess. I had problems with my spark plug socket. the rubber piece would come off and get stuck on the spark plugs.. so i had to set them all lightly.. then go back and lightly tighten them.. making sure not to lodge the rubber back onto the spark plug.

    i had 1 problem. I overtightened a screw on the coil. it broke. I'll replace it tomorrow...

    for today I'm keeping off of dirt roads and away from puddles.
  4. V8Cobrakid

    V8Cobrakid Green Handyman

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    btw.. first time breaking the spark plugs at 96k miles was easy. they look good... worn... used... but well.

    My old cars would look black by 50k.

    i'll post photos later.
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Perhaps it might help if you reserve the spark plug socket for use when removing the plugs. When installing the plugs, I use a length of rubber hose whose inner diameter will fit snugly over the spark plug tail. Then I will lower the spark plug into the spark plug well and rotate the rubber hose to start the plug into the threads. This eliminates the risk of cross-threading the aluminum head.

    After the plug is finger tight, then I pull off the hose and use a 5/8" (or 16 mm) deep socket without a rubber sleeve to tighten the plug to 13 ft.-lb.

    What broke: the igniter body, or the small bolt?
  6. V8Cobrakid

    V8Cobrakid Green Handyman

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    I'm aware of the tube technique. I used a 4 inch extention and my fingers.

    they all tightened to 13ft lbs so i assume they are fine.

    the bolt broke. so i have 1 coil just sitting there. I don't really care for this design. you can't torque those down at all.. and it's a gasket piece.. so even more need for a better and more secure method of keeping it tight. i kinda wish they used those clips that are found on the air box, or something similar to keep down pressure while latched.
  7. edthefox5

    edthefox5 Senior Member

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    Hey cheapskate that plug is missing its iridium tit. It's got alot of wear on it. Its only $20. You note how nasty the threads are on it. The threads are what kills you. To go through all the trouble of pulling them and not replacing them at 65,000. Jeesh.
  8. philmcneal

    philmcneal Taxi!

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    i changed my plugs at 192,000 km, it look like the gap didn't even changed. Too reliable I'd say, I changed them anyway, will post pic in the near future.
  9. hobbit

    hobbit Senior Member

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    It's *much* easier to get down in there, see things, and make
    sure you're not dropping any mung into the holes if you remove
    the wipers and cowl before attacking the plugs. Doesn't take long,
    and gives the opportunity to clean the accumulated muck out of
    the water gutter and drain holes.
    .
    _H*
    1 person likes this.
  10. joe350gt

    joe350gt It's too windy here...

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    Well, I bit the bullet today and did mine. I had to get a new spark plug socket as the rubber in my old one was shot. The new one had a swivel end which made it a little nicer to work with. Also had to get a 5" extension. The plugs broke loose without a big to-do. I'm at 105,871 miles and bought the car new on 10/27/05. The old ones looked decent for the mileage. I was going to wait until after vacation but decided to get it over with. I figured something would go terribly wrong but it was as straight forward as it could be with me doing it!! I did put a little anti seize on 'em too.

    Thanks to all the posters for their tips and tech info!!

    Joe
  11. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi Joe,

    Congratulations on your success!

    I suggest caution when using a spark plug socket with a U-joint. The U-joint may allow the socket to not be properly seated on the plug. In that case the porcelain tail of the plug may snap as tightening torque is applied.
  12. philmcneal

    philmcneal Taxi!

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    lol my case i had a u-ratchet, it was very nice! I hand tighten the plugs by a 2inch extension with the spark plug socket till i can't hand tight no more, by only then i'll finish off with the ratchet. I"d use a torque wrench but I did not have a 3/8 drive version as well the tight corridors didn't make it any easier.

    Oh and i didn't use antiseize, there was such a hot debate over the stuff i dunno i just followed Toyouta's example. If it wasn't a problem at 192,000 km i doubt there will be a problem in the near future... espically when there's oil on the threads and such.
  13. whiten

    whiten Junior Member

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    I just went to Checker and bought NGK Irridium IX BKR5EIX-11 plugs. That's what their computer said along with other options (including Platinum plugs - which I found interesting).

    Previous posts on PriusChat that I've seen have the spark plugs as a different NGK part number (IFR5T-11 if I recall). Then there's this article posted about the differences between Denso and NGK. I can get Denso from Amazon for about the same prices as at Checker for the NGK IX series.

    So two quesitons:
    1) Are the NGK IX as good as the OEM, and / or is it worth waiting and ordering the Denso from Amazon to get better gas mileage?
    2) More to the point of this email, the spec for gap quoted by Toyota above says the gap should be 39 to 43 mils. Yet from this page, all NGK -11 plugs are 44 mils, so why shouldn't we be ordering NGK -10 plugs with 40 mil gap?

    Inquiring minds want to know ;).

    Thanks in advance!
  14. patsparks

    patsparks An Aussie perspective

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    If you will never take the plugs out again then no need for antisieze but if you want to get them out again I'd use at least a moly-grease on the threads. Helicoils are great but better if you can avoid them. I have seen too many seized spark-plugs in my time. Oil is no good, you need the graphite or molybdenum.
  15. tochatihu

    tochatihu Senior Member

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    I replaced iridium plugs 2001 Prius at 115,000 miles odometer. They had previously been examined at about 60k. A lot of painful noises accompanied the removal process; I don't think they were anti-siezed when reinstalled at 60k (it wasn't me).

    Measured with a flat gauge none of the gaps were over 0.043 inches. However, the other electrode (the non iridium one) had developed a crater on each plug so the spark had to cross a larger gap. My opinion was the iridium was all still there but the effective gap was larger. It's probably fair to say that letting the plugs go much further could lead to overheating the ignitors.

    Unfortunately my photos of each plug are of poor quality and not worth posting.

    I encountered no particular difficulty in the job since the engine was quite opened up for the (first) PCV valve change at the same time. On that I can say that the original PCV valve still had a 'rattle' very similar to the new one so I suppose it was still working more or less OK.

    But man o man, that is a lot of digging to get to the PCV valve.
  16. jayman

    jayman Senior Member

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    Whether my Prius or my FJ, a dab of Loctite Nickel Anti Seize is put on the threads. I used to have a 2000 GMC Sierra with aluminium heads, and damn near gave myself a hernia trying to get those plugs out the first time.

    I wonder if the other owner appreciated the antiseize on the spark plugs, on that POS
  17. andyprius

    andyprius Senior Member

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    I wonder if spraying a bit of penetrating oil in the spark plug wells before replacing might ensure easy removal?
  18. SuziRider

    SuziRider '07 Prius &Hybrid'04 GMC truck

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    What is the difference between using the 'stock' 3324 Denso SK16R11 which actually have a fat .7mm electrode and the 5303 Denso Iridium IK16 .4mm? Is one good for 120k, and the other for only 60k miles? Isn't it the smaller .4mm electrode and lower voltage needs what is suppose to make the Denso better than the .6mm NGK? Is there any noticeable difference in gas mileage and useful life between all of them? They are all about the same price (around $10ea) on Amazon.com.
  19. patsparks

    patsparks An Aussie perspective

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    I'm not sure how it will get past the gasket. I guess if you loosen each plug a turn and pour penetrating oil in the tube and allow it to soak down it could help provided the aluminium head hasn't welded itself to the plug and already torn the thread out. Trust me I have seen this a number of times, a tiny dob of never-seize on the threads, easy.
  20. whiten

    whiten Junior Member

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    So I went ahead yesterday and replaced my plugs with the NGK Irridium IX BKR5EIX-11 plugs I bought from Checker. Replacement was relatively simple, and per a previous post, the only issue was with the right-most plug and its short wire. To overcome the 6" extension problem I jury rigged an extension from a 3/8" to a 1/4" adapter, then a 3" long 1/4" extension, and then back from a 1/4" to a 3/8" adapter to the socket. Total length of this contraption was about 5". My only concern here was having the sockets pull apart down in the spark plug well, and / or especially loosing one of the smaller adapters down there. But I was careful and it did not present a problem.

    FWIW, my car has 96K miles on it. Removing the original plugs was not a problem at all. Each of the four plugs rotated without what I would have considered excessive amounts of torque, and as previous mentioned in this thread, I maybe had to rotate them 3 or 4 turns before I could back them out by hand. I did put some anti-seize grease on the new ones though.

    Total time was less than an hour, and I hardly even got dirty :).

    I've only made about half a dozen short trips since replacing them. Seems like my gas mileage might be down just a little, but it's hard to tell with short trips. If it is, I wonder if it's a break-in sort of thing? Once I start commuting tomorrow I'll be able to tell more about gas mileage and whether it's changed one way or the other.

    I will say, though, that I think I do notice the engine idling a little smoother than before the replacement. There have been times in the past few months where I'll be at a stop light and the engine will run, and it has started feeling a bit rough to me. After the replacement, seems like the roughness got better. Of course, this is all very subjective, so who knows.
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