My new Prius Gen 1

I disagree with this statement:

1. The factory-installed iridium spark plugs do not have antiseize lubricant on the threads.
2. The Toyota factory repair manual is silent on the issue of using antiseize lubricant.
3. The NGK website recommends against the use of antiseize lubricant on the basis that the spark plug shell plating is adequate protection.
NGK Spark Plugs
4. The Denso website is silent on the issue, but provides a tightening torque spec assuming the spark plug threads are "dry" (hence, no antiseize or other lubricant.)
Spark Plug Installation | DENSO Auto Parts

I've replaced spark plugs on several Prius (without antiseize lube) and have not had trouble removing the old plugs, although I will admit that there is "drag" on the plugs due to the threads being clogged with combustion byproducts. I don't use antiseize lube upon installation of the new iridium spark plugs. It is important to observe the 13 ft.-lb tightening torque spec.

It is a reasonable idea to squirt some WD-40 or other rust penetration light lubricant if you are concerned about breaking an installed plug in the cylinder head during removal.

The point that I am trying to make is that the fact that a Toyota dealer mechanic did not use antiseize lube on the spark plugs, is not evidence of that person's incompetence. If you desire to use antiseize lube, that is your business.

 

The pot calling the kettle black, don't you think? However, I disagree, Patrick stated objective information and left it for the reader to form their own opinion.

The main point Patrick made (hint, point was not, "to use" or "not to use" anti-seize), which I'd like to reiterate is:

and it is disingenuous to make the implication otherwise. I'd also reiterate this statement:

No-one is saying you personally can't use anti-seize.

Anti-seize makes this a bigger possibility due to the real likelihood of over-torquing when using anti-seize.

Anyway I don't want to inflame the do I or don't I use anti-seize argument, as there is as many for as against, and I don't wish to change the minds of either camp. I just wanted to reiterate some of the statements made by Patrick in his balanced and informative post.

 

Brian, congrats on a tough job done!
Update on my latest project: Chap, again, my thanks for the 11V304 link. Saved me from making copies of the SA and SR section of the manual whilst I replaced the electric assist steering assembly on the '03 with one from am '02.
Why? The '03 with 140k miles had a cracked case (!) for the power steering assist gearbox. No sign of external damage; looks to me like an internal failure. Should be an inspection point for all Gen1 owners. Failure mode is potentially fatal.
I will, at some point, post a picture of the failed unit.
Lessons learned: If you're doing this on your driveway, support the vehicle with jackstands on the main structural members just behind the big bolts that hold the front suspension plate to the frame, and give yourself as much vertical clearance as you can manage.
YES, you will (at some point) drop the suspension plate off the car to remove the sway bar and steering mechanism. Be prepared to GRADUALLY drop the (VERY HEAVY) suspension plate down; I used a 2x12 board and a bunch of 2x4 blocks to support it, then carefully lowered by removed the blocks one by one.
HINT: access to the power steering electrical connectors is a LOT easier if you remove the cat converter and resonator assembly (it's not that hard; 2 bolts on either end, then wiggle the resonator out of the rubber mounts midship)(after loosening with a ratchet, I used a battery drill-driver with 2 3/8 extension shafts to unscrew the cat converter bolts, rather than banging a ratchet around my hand)(this is NOT in any of the manuals). The toughest task is unfastening the screwed-on ground connector from the flimsy bracket... vise-grips are helpful to stabilize the bracket while unbolting with a ratchet.
When I finished, I went to my local Toyota dealer for front end alignment and torque sensor recalibration (about $200, all told) (and to get confirmation that I did everything right)... and now handles like a dream.

 

Followup: Here is a picture of the failed electric steering assembly from my '03 Prius (140k miles). The casing fractured near one of the two bolts that holds the top of the gearbox assembly. From my examination, it looks like an internal failure, as there are absolutely no signs of external damage or impact... according to Toyota, the 11V304 recall service procedure had been implemented on the vehicle (on this steering rack assembly)(date unknown to me), so I presume that the failure occurred AFTER that service, while it was with its previous owner.

Is there a thread in Gen1 which relates to steering rack issues on the Gen1? I haven't found it, yet...

 

I never saw this post at the time, but that looks very much to me like the kind of thing that happens if some past mechanic removes that cap piece for some reason (possibly an attempt to get to the torque sensor), puts it back cockeyed without enough attention to the O ring, and then cranks the bolts down, first one then the other, expecting that to pull it down straight.

It does not look to me like a thing that happened by itself.