I’m way old school (76), and was taught that, unless physically damaged, spark plugs never wear out. We would remove, re-gap and clean if needed. I notice in your videos that you eyeball the old plugs, determine the gap is to wide and discard. Replacing with a new, not even checking the gap out of the package of the new plug (we always did that). Seems like this would be “non-standard practice” to me.
I suppose if you got them out, might as well replace them if you got the bucks.
Mike Sloan,
Whoever taught you that spark plugs don't wear out must have been from the Land of Oz.
Pretty much every spark plug for a modern car I've worked with has come from the manufacturer pre-gapped. I've seen some say to not gap them and get a replacement if it's not correct. My 1979 Catalina is the only car I've ever gapped plugs for, they're the old school copper variety. I'm guessing the reason they don't really want you to gap modern iridium or platinum plugs is those metals are way less ductile than copper, so the electrodes are much less tolerant of being bent before failure. DENSO says minor deviations in the gap are fine.
Spark Plug Installation - DENSO Auto Parts
I recently got a set of plugs for my 2014 Xterra and they were all gapped wrong - way off by .01". Sent them back for an exchange and the new plugs had the same gap issue. So I reluctantly ended up gapping them myself. The NGK website says they're suppose to be gapped for .044" at the factory but the ones I received were gapped for 0.035". A shop owner in a Nissan forum says he has received a lot of plugs that weren't gapped right so I guess you can't expect correct gapping. At least the plugs for my 02 Mustang GT came gapped correctly (+/- .002").
I don't have any experience with Nissan products myself. I guess that goes to show even more how much quality has gone downhill from that company per Scotty. Spark plugs are easy to manufacture compared to transmissions, etc. If they can't get the tolerance on a spark plug correct, I don't want to know how bad they are at adhering to tolerances on everything else in the car. Ford's not much better. 22k miles on a 2017 Mustang and I already had to replace the purge valve. OEM part made in Mexico.
Always check the gap with a feeler gauge. I never trust them out of the box. They were probably made on a Friday afternoon, or a Monday morning.
Actually a round-wire gauge is best for gapping plugs. Usually they come with a tab for adjusting the gap. (Note that in this video what is referred to as a "feeler gauge" actually has round wires attached to the feelers to do the measuring.)
https://www.youtube.com/watch?v=0OxUeD_TLHU
I have like 5 of those in the garage. Haha. I can never find one when I need it and buy them at the store, only to find them later.
I do that all the time with more tools and parts than I'd want to admit to!
{pear}:surprised:
In the old days we'd replace plugs at 10K-12K mile intervals, so you could clean and regap them and go another 10K miles or so. (I have a small air-powered sandblaster that's made for cleaning spark plugs.)
The plugs Scotty pulls out on modern vehicles typically have well over 100K miles on them. If you look carefully not only are the gaps large but the plugs are pretty beat-up overall. So best to just replace them and be good for another 100K miles.
They cost $3 which means I don't need to think for very long about whether to replace or not.
If I have any question about the viability of a plug, I'll put the ohm meter on it and check the resistance. If it's still good, I'll hit it with the wire wheel, clean the grounding electrode, re-gap it and re-use it. I like to think I'm frugal, my wife calls it cheap.
Yeah, I would never clean them and re-gap them as well...just get new ones.
