nitroracer

Just finished 5/6 spark plugs last night. I can tell you that #5 going from passenger side to driver side was very difficult, and I'm sure I did not use the elegant method. #6 looks to be physically impossible. I have the manual straight from Lexus and its sort of lacking, in my experience.

I was up against the clock and growing quite frustrated, so I buttoned up the car to make sure I could start it and off I went. Live to fight another day.

Will have to devise a plan on how I'm going to tackle #6 and hopefully can get it posted. Looks like there is a very deep and hard-to-reach bolt that anchors the main Engine Wire to the "Intake Air Surge Tank Assembly", which I'll need a dedicated angled ratcheting wrench for, rather than a flex head ratchet (with drive) that I was using.

s3v3n

iTrader: (3)

Small hands(wife) and a small wrench did it for me. Will take a pic of the wrench. I think some models/years(earlier), the intake manifold will need to be removed. I have a 2017 model and didn't have to.

nitroracer

Which screw? I'm not convinced this one even needs to be removed. The manual says nothing about it. The one I am referring to I believe is the bolt holding the Wire Harness Clamp Bracket in place.

I'm thinking if I can remove the clamp from the Engine Wire closest to the windshield, that should provide enough clearance.

Do you have any pics?

Sasnuke

I was wondering how much mileage you have on your 2018? As the plugs have a very long service life on the V6...I have a 2014 IS250 and it still has the original plugs as the car only has 85,000kms.

syed4gr

I remember having to cut open a couple of factory zip ties to move the wiring loom out of the way. Replaced them with my own zip ties later

nitroracer

Just over 60k miles. I do a lot of driving. In fact, it dawned on me that I'm probably the only one on this forum with a 2018 or later of any model that has hit this milestone already.

Lexus has this replacement as a requirement to maintain the Emissions Warranty.

I finally got the last spark plug out and a new one in, but I had to do it in a roundabout way and unfortunately, the metal brace that keeps that portion of the engine wire anchored to the main engine block is no longer screwed down. There isn't a tool in the world to get that bolt back in. The plastic engine wiring is locked onto the metal piece via some sort of tab lock. It has to be undone to access the 6th plug the way Lexus intended you to. Unfortunately, this tab lock is at the *bottom* of the engine wiring and it's impossible to see how the tab works and thus how to unlock it.

Therefore, on the 3IS at least, I had to unbolt what I'm guessing you guys call the "screw from hell". Unbolting it was actually quite easy. Going in reverse was dang near impossible. It's also not called for in the instructions - it's the clamp at the far right of the next image. Notice the dotted line box is highlighting the *underside* of this clamp.




In examining the design while I was under the hood, I have to say I think this metal bracket/clamp (called the "Wire Harness Clamp Bracket" according to the service manual) doesn't serve any real purpose. The large wiring harness ("Engine Wire") that envelopes the entire engine like some tentacles (the bolded graphic on the above pic) is secured in so many places that by the time it exits out toward the 6th spark plug, it's already completely secure and not moving an inch. Heck, I had someone rev the car while I was under the hood and can confirm that even when unbolted, it doesn't vibrate/shake/move in any way at all.

I've been unable to locate the exact part number, but will try and post here when I do.

I, too, destroyed a bunch of plastic clamps, as well as zip ties of the permanent variety (the ones that are anchored to a tab like a drywall anchor). All replaceable, but I don't think I care enough to track down the part numbers and order them one by one. They still serve their main purpose.

No matter, the spark plugs have been serviced and today I will be tackling the ATF, front and rear diff oils. It's like the SAT Exam - just move on to the next question

Mathsss

Hi planning on changing my plugs in upcoming weeks. Will buy probably from Rockauto as they are like half price of Canada's price (14 instead of 27 CAD). Does anyone noticed cracks on boot? Did you buy boot kit also? I am at 120K KM where service was supposed to be at 96K KM

Mathsss

Anyone? Change boot kit or not? Better to buy 1 boot in case?

Sasnuke

As this will be your first plug change, I'd like to think the boots will be just fine.
Worse case if one needs replacing, swap the coil with another one on the engine that is the easiest to get to...that way if you need to change the boot it will be quick and easy.
But honestly they should be fine.

H-I-M

iTrader: (1)

Has anyone changed there plugs & then have a check engine light come on? I have a 2014 IS350 AWD. Thanks.

JNP1227

iTrader: (1)

What is the code? What brand did you use? Did you re-torque and check all connections (spark plugs, coil-packs, wires, etc)?

H-I-M

iTrader: (1)

I used the Denso plugs & everything was tight & plugged in. P0348 camshaft sensor A circuit high bank 2 & P0393 camshaft sensor B circuit high bank 2