Spark Plugs

Those sound like options. Maybe even try a universal in there at one point. I like your thinking.

 

Unfortunately not going to work: the actuator extension down to the sparkplug is a solid metal sleeve. You can disconnect it and raise it about 2 inches before it hits the u/s of cowl.

 

I'll have to see when the time comes. Got a lot of toys in my box for getting into about any hole. Sometime we think they built the plane around the things we have to get at regularly, kind of like how cars are now. You know...ease of assembly, not ease of maintenance.

 

So you're saying that the plug coil needs more space to be removed?

I've done a thing with a short extension to a conventional socket slipped over a spark plug socket to change plugs in a '97 Subaru Legacy Outback. The DOHC engine has the spark plugs horizontal in the center of each head, directly opposite the frame member that supports the front bumper. Pain in the butt.

 

As Mendel mentioned above, the issue is not about reaching into the spark plug tube, but that the ignition coils cannot be removed because they interfere with the cowl.
I agree about how modern cars are built. On the new Camaro, to replace the A/C evaporator or heater core the windshield must be removed to access two bolts for the instrument panel support. Replacement of the EVAP vent solenoid valve requires dismounting the rear sub-frame.

 

How far would you have to rock the engine forward for them to clear the cowl? In my GM U-van that's the approved method for accessing the rear bank spark plugs.

 

This afternoon I went through the steps as outlined in the video by nutzaboutbolts. Again, many thanks, would have been swamped without it. Tons of detail, all the gotchas noted, very thorough.

The main stumble: I had a 5/8" sparkplug socket, and it appeared to be just spinning on the plugs. I checked the video again and it's saying 9/16" is what's needed. Walked to my nearby Lordco, near closing time. They told me there was no such thing as 9/16" sparkplug socket, and (of course) they didn't have any. I finally bought a deep, 6 point, 9/16" regular socket, and managed to transfer the rubber insert from my 5/8" spark plug socket. And it worked, grabbed the plug securely, whew!

By the time I was buttoning up I was getting pretty punchy, it had been a long day. Put the the plastic trim back on, then realized the wiper motor and linkage was still sitting on the floor...

Finally got there, but many of the steps that look easy in the video took me 2~3 times as long, LOL.

 

Yeah, I would recommend using a regular 6 point 9/16" deep socket to just remove the spark plugs and then use the rubber to take it out since the 9/16" spark plug socket is too short due to the rubber inside there that holds the spark plug and you won't be able to loosen it unless you press down real hard. glad you got it done! You saved yourself a lot of labor money haha...

 

You can also use your coil pack to remove your spark plugs by loosening plug first push coil in and pull out

 

I got lucky, the rubber insert seem to work ok transferred to 9/16" I got, but that's a good point: I could have just picked up the plug with my regular 5/8" spark plug socket, it would still grab ok.

It is a frustrating amount of labour to disassemble. Our previous Honda Civic was similar, cowl had to come off, but at least the wiper assembly could remain in place.

 

Probably will take you only 30 mins next time tho

 

Good thing the plugs last 100,000 miles.... sheesh.

 

Am I right in thinking the valve tappet gaps are controlled hydraulically, ie: no adjustment necessary, or possible?

(It's just that when you've dug down to there...)

 

Yes, hydraulic, no adjustment (finally Toyota saw the light on this one).

 

Is it worth it ? Mine is due soon (182000 km). But the motor is running fine, no issue and oil is clear after a few thousands km. I don't feel it needs spark plug replacement.

 

Maybe they don't.

Sparkplugs are awesome these days and Prius cars are pretty easy on them. I've got an 11 year old Chevy Venture with the original plugs in them with no symptoms of illness.

 

There was a poster a while back who chased a misfire issue he had with a Gen II that was driving him nuts and finally found one of the ignitor boots had a hairline crack in the rubber that could not be seen unless you pulled on the rubber. High Voltage was leaking out of boot to ground. Great post.

So..because of age may not be an issue on a Gen II but I would still take a moment & clean the outside of the rubber ignitor boot and check carefully for any cracking or hardening of the rubber and maybe not a bad idea to put some rubber trim conditioner on the outside of the boot like Black Magic Protectant which is my favorite.
In addition to dielectric grease on the spring inside the boot.

 

I'd use the dielectric grease inside and outside on that silicone rubber boot, and any seal at the top of the coil to head surface. Other products may be conductive. This high temp grease is not. I wouldn't use it on the conductive metal parts.

Question: Are the stock plugs double iridium or platinum?

I may set a record on leaving them in the longest. I agree, the Prius is very gentle on plugs.

 

They're iridium. It's a royal pain to get at them, see NutzAboutBolts excellent video on the subject.

From 562 of the manual:

 

Some plugs have iridium on the electrode and the ground post, "double".
Either way, I'm taking it to the limit!!

Some cold, dark, damp morning when I really need to get somewhere, I'll feel it missing or, hopefully not, it will fail to start.