Spark Plugs Maintenance Schedule?

Denso SK16R11 has a recommended life range of 80k-100k miles

OEM calls for the Denso SK16R11 or NGK IFR5A11

Personally, all 7 of the Gen 2s I commonly work on have all had the Denso and have been flawless.

DensoProducts.com: SK16R11 $7.69 Denso 3324 Iridium Spark Plug - Best Car SparkPlug Replacement

 

I would be way more concerned about the health of the hybrid battery than the spark plugs. There all dying on the G2 platform from lack of driving. First sign of failing health Is poor mileage then purple bars real fast and slow and longer blue bar recovery then that turns into $$$$.

 

How do these plugs compare to the NGK Laser Iridium IFR5T11 (4996)

Do you think the Denso ones are superior in terms of longevity?

 

You can download PDF format Owners Manual and Scheduled Maintenance Guide at Toyota Tech Info site, in the “Manuals” Tab.

The scheduled change interval is in the second booklet, and the specd plug in Owners Manual.

 

Here's a link to a discussion that's relevant. One of my first threads I was part of way back when in 2012: OEM Recommended NGK Spark Plug Part Number Change | PriusChat

 

I'm not able to provide information on that. The first Prius I bought had the Denso's and I've never had the opportunity to try the NGKs. Sometimes it seems different cars just 'like' certain plugs. If I ever had one start acting weird, I wouldn't have a problem trying the NGKs to see if it liked them better. Maybe I'll buy a set to install anyway on the next family car that comes due. Mine has about 62k on the current set of Denso plugs.

 

this should be so simple...

 

spark plugs do not cause bad mileage unless they have 300,000 miles on them .
Majority of the cars power comes from the hybrid battery.
All your seeing is green....no thats not true your just not paying attention but you will very soon when it starts getting old.
Green does not last long but means the battery is very charged at least from the drivers perspective.
Watch the battery behavior on the mfd. see how fast if it goes to purple bars and then how fast it recovers to one blue bar...then 2

Failing battery packs are a real common post on this site.
Sparkplus
last change I used SK16s spark plugs lots of counterfeits out there I bought mine from Olathe Toyota on line. They run perfect.
Already gapped don’t touch them.
.
If your going to replace the plugs replace the valve cover gasket too and the PCs valve it’s all open then it’s easy just use some black gasket sealer on the front of the engine block to make sure it seals. Then When you take the v cover off use a box wrench on the PCs valve.

 

It's likely in pretty decent shape. How quickly (or slowly) it goes up or down depends on how much capacity the hv battery has as well as how you drive the car. I refurbished the pack in my 2006 a few months back- it now measures at 5.5 Ah. I also drive 80 miles a day- mixed interstate cruise and local highway with moderate hills. I usually see the meter stay at 6 (blue) to 7 (green) bars- sometimes it hits 8. It can drop to 4 bars on extended uphill or stop and go driving.

As long as they are genuine, both Denso and NGK are great spark plug brands that have been used as OEM by many car makers for decades.

Posted via the PriusChat mobile app.

 

Why in the world would you want to change a valve cover gasket on a Prius? When I had a blown exhaust gasket cause a valve cover gasket to fail most auto parts stores said they couldn't get the part and that they never once seen someone order it.

I mean I grew up in the 70's and 80's and understand why valve cover gasket replacement was considered expected maintenance on an old engine, but that was technology that's now 1/2 century old. There's no reason to replace this in a Prius as a preventative, only if it somehow gets damaged.

 

Well maybe if taking a few bolts off the valve cover and replacing that inexpensive gasket gets your nightgown in a bunch you should stay in the shallow end of the pool and concentrate on spark-plugs. But most people who have had only a cursory association with working on 4 bangers know the gasket weeping/failing at the spark plugs well is really common even on a well cared for motor.

 

First I said I already did a valve cover gasket once, and it was alot more than the spark plug well that was the problem, but it was simple-easy. Second, if a bad valve cover gasket is "really common even on a well cared for motor" than how is that valve cover gaskets were so hard to find and auto parts store didn't have access to them and I was told multiple times that they've never heard of anyone ordering that for a Prius?

 

Again, you can download at Toyota Tech Info. Go to the Manuals Tab, enter your info and search:

 

was not directed at you it was directed to the guy that busts my chops all the time.
You’ll know if it needs a gasket if you see oil on the plug when you remove the plug. I used my bore scope to checkout the plug well and saw some oil on my my really really well maintained car. Very common on this site for gasket to leak a little at the plug hole,
You can use your iPhone to take a picture too just take a pic of the spark plug hole to see if any oil in the hole before pulling tithe plugl
Very easy to take valve cover off and then very easy to take the PCv valve out too with the cover off that valve is due also.
Seen many busted valve covers on here with people trying to remove that valve with the wrong wrench and knocking a hole in the cover.
Gasket available at the dealer.

 

ed,

Step back and look at this again. The average person that is going to DIY a set of spark plugs (perhaps even for the first time) is in no way, shape or form, ready to be just casually popping off the valve cover to replace the gasket. Your post even talks about using rtv and how people commonly break the cover due to using the wrong wrench. Even if the cover had a minor seep, there's about a million ways this could make a nuisance problem into a significant problem.

Hell, half the people here think you need to pull off the windshield cowl to swap plugs on a Gen2. The random guy trying to do the valve cover gasket will probably end up with leaks 10x worse than he started with.

Many gen 2s in the 'extended' family. None have leaks in the spark plug wells, or anywhere else around the valve cover. All have original gaskets. This may not be as common of a problem as thought.