Sparkplugs after 148,000 miles

Are we looking at the same plugs? I see no wear there either.

 

Compare to the new plug. It's not that difficult.

 

I did, there is no wear on the ground electrode at all. What would cause that to wear, the spark jumps from one irridium pad to the other. Even if it does have some wear, it wouldn't affect the operation of the plug.

 

Worn out plugs get stuck in the motor or the electrode falls off and knocks around destroying a valve or scratching the cylinder bore. Keeping plugs until they are visibly ruined is a false economy. Like driving on tires until they pop.

 

I agree with Mr. Electric. Change your plugs just to be safe, they're not that expensive.

 

They look worn to me. In the top photo, the new plug has a much longer center electrode than the worn plug below it.

 

I agree that you could probably clean those plugs and they would fire right back up. They have alot of miles on them but would work fine I bet. Very high quality plugs.

But its not a bad idea to replace them at least every 100K just for possible thread corrosion.
Nothing worse then boning up the sparkplug threads in an aluminum head because the plug get stuck. Lot of galvanic action between the plug thread and the head. You can how corroded the threads are.

Especially on a prius that could be leaking water past the hood dam and then it drips right on top of the igniter and gets in the well. These plugs look very clean on the glass top I see no rust on the plug porcelain so the water dam on the op's car is ok.

I like to freeze spray plugs before I take them out. Roll up thin cardboard around the plug to isolate it and freeze the sh*t out it.
Comes right out really easy as the plug shrinks away from the head when frozen.

And look carefully at the top of the valve cover for corrosion and very carefully in the sparkplug well and in the igniter tip for any corrosion on a Prius. Look in #1 hole for any oil because if oil spills out of the oil fill hole during oil change fill up thats where it goes....into the well. Apply dielectric grease to igniter plug mating hole and some in the igniter B+ connector.

One poster with misfire issue found an igniter boot that covers the sparkplug was finely cracked allowing firing to get past boot. Could not see it unless you pulled on the boot. Probably good idea to check that and if ok apply some rubber conditioner to the boot too.

But at 148,000 may have been a good idea to replace the igniters too.

 

Awesome idea with the freeze spray. I want to try that next time I get stuck on some old plugs. I may try it on a junk motor first to get the hang of the technique.