NGK spark plugs

In 30,000 miles when you need plugs, I think they will be just fine.

 

Service interval in Europe is at 90,000 km, I rejected a change that soon, but will probably do it at 120,000 km.

There are also Denso Iridium TT (IXEH22TT) comapred to OEM SC20HR11, they have 0.4 mm diameter center electrode vs. 0.7 mm. Any idea if this is any better. OEM-s at the dealers are a little more more expensive, but not that much that I would go for alternative unless there are other benefits.

NGK Iridum IX have 0.6 mm diameter center electrode.

Any thoughts on best option?

 

oem denso are cheaper on ebay 8 each

 

But how do you know that merchant is selling genuine merchandise? These plugs really do use iridium to gain their long, 120,000 mile life.

 

100% rating and oem packaging

 

at 120,000 miles, how impossible will these plugs be to get out?

 

NGK and Denso are very close, either would be fine. On our previous Civic Hybrid there were 2 spark plugs per cylinder, and Honda installed one of each (one Denso, one NGK), on each cylinder. I guess they had an obligation with each company?

Do watch @NutzAboutBolts 's video: 90% of the job is getting TO the plugs, a lot of disassembly is required. I'd recommend a very thin application of molybdenum anti-seize compound on the new plugs, and torque to 13 lb/ft. You will need a 9/16" spark plug socket and at least a 6" extension.

 

I've just had some spark plugs that were difficult to loosen... once I got to them. But, have never waited 120,000 miles with an aluminum head.

 

i'm a big fan of denso TT plugs (the most advanced plugs available), but it's my understanding none are available for prius. are you sure about it?

anti-sieze is fine, but one has to decrease the nominal torque or the plug will be over-torqued by about 20%.

 

@friendly_jacek Yeah 13lb/ft is reduced a bit. The spec in the second pdf I attached above says 15, presumably for dry threads.

I'd say apply a light coat of anti-seize, then clean it off the best you can with a rag, count on there being a slight residue in the threads.

That's what I did anyway, just an inspect and reinstall.

 

The Toyota spark plug inspection procedure Mendel posted includes this note:
"If the (spark plug) electrode has traces of oil on it, clean with gasoline before using a spark plug cleaner."

What kind of "inspection" is that? "We pulled your spark plugs, they were covered with oil, we put them back..."

If your plugs are contaminated with oil, you need to fix whatever caused that.

But the valve cover gasket job doesn't look too bad. I had to do one on my BMW 328, and the entire cover was plastic, and easily damaged.

 

That I had to post TWO PDFs is testimony to how messed up the repair manual is. Common sense would dictate to include the spark plug torque value WITH the inspection, but nope: it's halfway across the galaxy, lumped in with valve cover removal.

As far as inspection, I wouldn't use any sort of abrasion on the plugs, just solvent and some sort of soft brush, say an old toothbrush. Also, the plugs come pre-gapped; I would check gap but wouldn't attempt to adjust.

 

Changed mine at 145XXX miles and all came out normal. Replaced with original Denso Iridium, the only difference in the ones I took out with 145XXX miles and the new plugs was the color, no sign at all of tip erosion on the old plugs. If I'd checked the old plugs before ordering the new, I would still be using the original.

 

I'm not going through the deconstruction to open it up and not replace them...LOL

 

I've taken ours out twice now without replacing, but then: I need therapy, lol.

 

This is odd. Isn't the US spark plug change interval 120,000 miles? That would be about 190k or 200k kilometers. Am I mistaken?

 

Canadian 2014 schedule says 192,000 kms or 144 months (12 years).