150k on spark plugs experience?

i changed out my plugs around 97k miles.. it was rather easy.... i was thinking about seizing too.. yet had not difficulties.

 

whodat, it may be actually the case in California that you are supposed to replace spark plugs at 100k miles. This is my recollection.

Anyway, I would not wait much longer for that, either. If you DIY, use the correct iridium replacements (2 choices) and make sure your plug wrench is well-seated before torqueing them out. Mine made rather horrifying sounds as they unwound from the aluminun cylinder head. New plugs should get anti-sieze on their threads.

Photograph the electrodes of the old ones close up if possible please. I have an interest in electrode erosion.

 

If they've been in there that long, once you crack them and they
start turning, work them gently back and forth and go SLOWLY
in a net loosening direction as you do that to remove them.
Hopefully they haven't bound to the head metal tight enough to
cause damage. The forums have advised removing all the plugs
earlyish in the game and getting some anti-seize on the threads,
but if that's never been done then high caution is in order.
.
We could only wish Toyota had anti-seized them at the factory...
.
_H*

 

Is there a torque spec for the plugs? Would anti-seize cause over torquing? Thanks!

 

13 ft.-lb. If you use anti-seize lube, apply a small dab on the spark plug threads. I would not worry about over torquing.

I question the 150K mile change spec in CA since the iridium plugs are the same in all Prius and the service interval spec is 120K miles elsewhere. The Denso website suggests the original equipment iridium spark plugs are good for up to 120K miles.
http://www.densoiridium.com/faq.php

My guess is the extended CA spec is for regulatory reasons, not technical reasons.

If Dave is concerned about waiting until 150K miles, nothing prevents him from changing the plugs now (I changed my plugs at 100K miles).

 

You will find that a few cranky old PC-ers are selective on which of Toyota's recommendations should be followed exactly. T. does not see much reason to change transaxle fluid either. That is another story, of course, but perhaps you would consider doing it after wrestling with the sparklers?

 

Y'all [particulary DAS] saw my pictures of variously worn vs. new
electrodes, right?
.
_H*

 

I'm at 152,000 right now on the original plugs. I'll probably change them at the next service for another 150K miles.

 

I changed mine at 113k miles and I wish I waited until 150k miles. They were still in great condition.

 

Did you measure the gap of the used plugs? Regardless of physical appearance, 1 - 1.1 mm is the spec and they should be replaced at 1.2 mm.

 

I still have them... when I get the tool to measure them, I'll post the results.