Changing spark plugs

Plugs should have been changed at 120 k. When you bought the car, did they have any maintenance records of what was done to the car? If they pushed the plugs, what else might they neglected to do? I assume you were getting some engine knocking or a code and that prompted the plug change?

Other people have posted pictures of their plugs on changeout and look similar.

 

It's hard to tell from the picture, but you're likely right: probably original. They look in pretty good shape though. Now you do know when they were changed.

Did you do them yourself? Isn't that a lot of fun, pulling out the wipers, wiper motors, windshield cowl, lol?

 

Plugs in good shape will have a gap that is within spec, and a brown color. Your image is a little small, but they look good to me. What you don't want to see is dark black (rich mixture) or white (lean / too hot).

Changing spark plugs doesn't require skill; it requires a spark plug socket, and a wrench. Perhaps slightly more complicated than filling the gas tank, and less than changing a wheel.

 

A good variety of ratchet extension bar lengths is handy. I just did our daughter's Pilot, had on hand a 3" and 6" extension, could have used a 1.5" extension too: no matter how I juggled it was either a bit too much or little. A grabber tool came in handy too: I was using a spark plug socket for the first time, it's rubber insert was grabbing so good the socket came off the extension, stayed down in the tube when I was putting the new plugs in. And a low range (likely 3/8" drive) micrometer torque wrench, something capable down to 10 ft/lb. And a tin of anti-seize, well some use it, some don't.

With anti-seize 13 ft/lb torque is good. I believe the spec is 15, but that's with dry threads I assume. I've attached a couple of relevant doc's. In typical Toyota Repair Manual parlance, there's a section on the spark plugs, and torque value is halfway across the book, in the valve cover section.

And in the spark plug doc, there's no mention of the half hour of solid labour required to dig down to the damn plugs. For that check out @NutzAboutBolts 's video, pinned in the third gen maintenance section.

 

I tried to zoom in on the tips of the plugs in your picture, and I think they look more like Redpoint5's spark plug picture #7, which is to say, a bit of carbon fouling. They definitely did not have the light tan colour I would want to see, and the seepage rings just above the metal on the insulator suggests that the internal gasket between the ceramic insulator and the threaded metal she'll was in fact getting old and letting some combustion gasses leak by over time. Not terrible condition in my book, but bad enough that I would feel much better having replaced them. If the gaps were over spec and if the carbon was allowing a suboptimal spark arc, I would hope for a bit of mpg improvement with the new plugs.

 

Both should be done. There are videos here to show you how to do that. MAF is 2 bolts and it comes out. To access the throttle body, you'll be removing the intake hose, but still very doable .

 

Out of curiosity, did you get the SC20HR11 plugs from Toyota or the newer SC16HR11 that Toyota superceded the old part with? I just posted in the maintenance section about the new plug specification from Toyota and how it's a heat range hotter now. I speculated it may be to reduce the amount of fouling due to the plugs not getting hot enough the way a lot of Prius drivers drive (slowly).

Gen 3 Prius Spark Plugs superceded with hotter plugs | PriusChat

As for cleaning the MAF and Throttle plate, all you need (besides the cleaners and rags) is a 10mm socket, 8" extension (or longer), and 15 minutes (including the cleaning). Three bolts hold the air filter box in place (one hidden under the engine cover) and three more bolts for the snorkel that goes to the passenger side. Remove it all at once. Then squeeze the clamp for the remaining tube to the throttle body. The clamp has a locking feature so it's easier to remove and replace. Once you remove that tube, you have clear access to both the throttle plate (open it with your finger or a PLASTIC rod; don't jam it with a screwdriver) and the MAF sensor (one 10mm bolt holding that in place). If you're REALLY daring and have 30 more minutes to spare, you can remove the intake manifold, PCV valve, and EGR pipe and clean those out. I did everything in 1 hour, including hunting 15 minutes for my 10mm socket that fell into the engine bay, but ended up being under my other car... I'm sure there's plenty of youtube videos out there if you need visuals.

 

anyone know about how much it costs to have the plugs replaced. Dealer wants 300.00. thanks

 

I don't think those brown rings on the ceramic are a problem. My plugs had them, and I saw that on the photos of everyone's used Prius plugs.

 

Probably half that anywhere else. It's easy to do and only takes a few minutes and basic tools except for a special plug socket that holds on to the plug as it's removed.

The dealership is never the place to take your car for service since it will always be the most expensive option. An exception to this might be for things specific to the hybrid components of the Prius.

 

Thank you

 

That's a bit steep for sure. I'd guesstimate in the states four plugs would be about $60. There's a bit of wrinkle with the labour though: the wipers, plastic window trim, wiper motors and metal cowl all need to be removed, before the spark plugs. And then reinstalled, lol.

For professional I guess an hour max for labour. See @NutzAboutBolts video, pinned in maintenance forum. They manage it in about 40 min (?), and have mentioned it would be faster with power tools.

 

I paid about $42 USD for the four special Denso spark plugs, plus you need some anti-seize and dielectric grease.

I think $150 labor + $50 parts is reasonable. It's quite a bit of labor; far more than any spark plug replacement I've ever done.

 

I've had that happen, too. Just pull the rubber insert out of your spark plug socket, trim off about 1/3 of it, and put the shortened piece back in.

All you're trying to do is make sure that the socket will hold onto the plug.

 

build-in magnet/
worth every cent/

www.amazon.com/gp/product/B00BP5RTEE/ref=oh_aui_search_detailpage?tag=quickview-20&ie=UTF8&psc=1

 

I had been using a craftsman plug socket as my tire lug tool until it broke (sears replaced it ). I now use an impact socket (case hardened steel).

JeffD

 

I replaced my plugs assuming they were fouled from oil over fill. @40k and they were wet. They didnt smell like gas. To change the plugs is not difficult just takes some time. Follow the nutz and bolts video. Thats exactly what you will experience.