Spark plugs

If you already have the windshield cowl removed for maintenance, you should just go and do the plugs at the same time. Once done, it'll be good for another 120k miles. For most people it's a 1 time event, as they normally won't keep the car long enough to do it again after 120-150k miles

 

Sounds like miles and months are close to sync'd anyway, but fwiw, the regular spec for plugs change is 120K miles or 12 years, whichever comes first.

If DIY'ing get the plugs from a reliable automotive retailer or dealership, avoid EBay; there are lots of counterfeits.

Note: the orignally spec'd Denso SC20HR11 has been supersceded with Denso SC16HR11 now, slightly hotter.

Good video by @NutzAboutBolts, on how to get to the plugs:

In the video they slather anti-seize on the plug threads, then torque to 20 foot pounds. Repair Manual (excerpt attached) says 15 foot pounds, and no mention of anti-seize, so presumably clean/dry threads. If you do use anti-seize, keep it light and reduce torque to 12~13?

 

and clean the egr circuit, pronto

 

I removed these today from my 2015 Gen 3 Prius with 162k Boston miles. These are the original plugs. They probably could have made 200k.

And off course I found the obligatory rodent's nest I thought I had neatly side-stepped. Luckily I didn't see any damage.

 

Good to know they can easily go that far. Just for curiosity, how wide have the gaps grown at that mileage?

 

We are finding the spark plugs are not reliable beyond 120,000 mi. I would even suggest to replacing them at 100k to have a round number that's easy to remember and reduces your chances of putting access strain on your coil packs which are vulnerable to premature failure anyway

 

How they look, they’ll make it to 200k with misfires along the way.

 

I’m coming up on 12 years, the CDN spark plug change interval, AND at 95k kms. The kms criteria is 192k km IIRC (120k miles), and I’ve already resolved: I’m leaving them be till year 15, the next coolant change interval. Will do the coolant, take off the wipers to do plugs, and revisit EGR/intake cleaning.

I did pull the plugs once previous, around 50k kms, just for a look.

 

I bought my replacement plugs at the dealer because of all the fakes around. The new plugs are Denso SC16HR11 and the originals are SC20HR11. I eyeballed them and the gaps looked identical - but I didn't measure them.

BTW - the originals came out really easy.

 

Any idea why they went to a hotter plug?

 

Michael: on the official site I'm seeing heat range 20 is still spec. Where did you get your information?

BPR6ES was used on some Kawi and Nissan engines in the 80s and 90s. We had a problem with 6es failing and the fix was to use 5es plugs. Can't imagine going 4 heat ranges of change.....


Spark Plugs. 2010 Toyota Prius Base | Toyota

 

My 2015 owners manual does say SC20HR11 is spec but Mendel straightened me out on this. Here's the bulletin - https://www.denso-am.eu/news/june-2017-product-bulletin-supersessions-within-the-spark-plug-range.

 

Just ask dealership parts department; they get these updates. And doing it over the phone, you “can” hang up and buy elsewhere, if their prices are prohibitive. OTOH, if it’s a buck or two more per plug, and with counterfeits circulating…

interesting, in the link they even advise spark plug retailers to sell off their “20” stock, before moving to “16”. In other words, it’s NOT that critical.

our 2010’s still got the “20” plugs, they looked fine when I had a look at them (around 60k kms IIRC). Technically “due” this November, the 12 year mark, but I’m stalling to 15 year mark, when coolant changes are due again. My justification for delay: only at 95k kms currently.

will revisit EGR at that time too.

Unless I fall in love with 5th gen. Suspect I won’t. Or will be able to restrain myself. Maybe…

 

Glad I found this thread! Since you said if removing the windshield cowl you might as well do plugs. I plan on installing f-sport lowering springs on my CT and they mention that you should remove the cowl. On top of that my car came from FL so the cowl is completely faded and I have a new oem replacement sitting in my basement. Figured while I do springs, I would install the new cowl... might as well be doing spark plugs to the list .
Nothing worse than taking something off then having to do it again because you could have done XYZ while that part was off...etc.

Excellent info on the superseded spark plugs. Question. Since they run slightly hotter what exactly is the benefit to that?

Thanks,
-Nigel

 

Less prone to develop deposits?

If you've never removed the cowl before, video here about spark plug change (#13 IIRC) is informative. Mind-numbing amount of wrenching though. It takes me about 3 times as long.

Sorry, forgot link:

Nutz About Bolts Prius Maintenance Videos | PriusChat

 

Awesome! Thank you for that. Doesn't look too bad but definitely looks like it makes the job easier removing it and since I'm replacing it no need to not get to the spark plugs. I have noticed that The denso plugs are the following: Denso 3499.


These are about $9 per plug. I called the Toyota dealer by my house and they just quoted me about 22 per plug...ROFL.

I checked the Toyota Part number on McGeorge (Had I known this I would have bought them when I bought the oil filter housing spin on ..)


They have them priced at around $8.50 which is way more reasonable. I kick myself for not checking first now I'm going to pay double shipping...

Ebay always has good prices on parts but anymore half the stuff is fake. I'd rather either get them from RockAuto or Toyota (but not my dealer cause they are wack with prices).

-Nigel

 

I bought them from McGeorge in July for $8.95 apiece, plus tax and shipping
Coincidentally, I lived within 2 miles of their store 1993-95, long before I owned the Prius..

 

Correction, everything on eBay is fake