When to change spark plugs

[Sman]

TL: DR below
So I googled how to get better MPGs out of a car since my 2004 Alero has 210,000 and is in great shape. The first site that Google suggests is http://www.carbibles.com/gasmileage.html and reading the steps some of them make sense. The only one that didn't was the mileage on #8 (see below)
8. GET NEW SPARK PLUGS
Spark plugs work in an incredibly hostile environment. If you've got more than 30,000 miles on yours, change them. Fresh plugs that aren't covered in carbon desposits will certainly help you in your quest to become a fuel miser.

Now I have never done any maintenance on my engine and transmission other then fluids and filters. I get the same mpgs that I have always gotten since I bought it 13 years ago.



TL: DR website states to change spark plugs every 30,000 miles........does anyone do that?

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[inv4zn]

Just as a rule of thumb, I change mine every 2 years. I donno if MMI or Honda's schedule includes spark plugs, but $50 every 2 years isn't that bad, and relatively easy to do.

I'd think if you had a V6 with the rear bank close to the firewall (as my old V6 Accord, ugh), or worse if you have a boxer engine, then you'd avoid changing more often than necessary, but with our cars it should take less than 15 minutes for all.

Also worth looking into is if your car has a distributor, and changing out the dizzy wires if they've never been replaced. Your car may not have them, I donno.

 

[josby]

Yeah, the MM item number 4 is to change the plugs and check the valve clearance.

No way of knowing for sure when that number will come up, but as a point of reference, that is also MM #4 for my S2000, and the maintenance schedule for earlier model years (which did not have MM but did have the same engine) was 105K miles or 7 years for doing the plugs and valves. Also, I remember doing the plugs and valves in my 2005 Civic at either 105K or 110K.

So from those two I would guess that MM #4 will appear somewhere around 105K miles on our Civics, depending on driving conditions.

 

[inv4zn]

^He doesn't drive a civic, it's a 2004 Alero lol

 

[josby]

Wait, why is he posting here then, and why are we answering his questions?

I thought he was just saying he'd done it on his Alero and wondered if he should on his Civic too.

 

[inv4zn]

Wait, why is he posting here then, and why are we answering his questions?

I thought he was just saying he'd done it on his Alero and wondered if he should on his Civic too.

Because we're kind, helpful people of course

I'm not sure, but it was a simple and innocent enough question that could be useful to other members.

It's the 84th repost of "which HIDs should I get" that I tend to ignore.

 

[Sman]

Still waiting on my ex civic hatchback with sensing to arrive....That was ordered in November

I was just seeing if anyone changes them every 30k miles like the site said.

 

[Billy4202]

Should be go to go for 100k like everything else these days. I've never heard of anyone doing them at 30k, some of those hypermiling sites are filled with junk info that doesn't do much in the real world.

And when your hatch does arrive - you'll get good enough gas mileage that you won't have to do extra to eek out those MPGs.

 

[peterletran]

This mighty be off topic, but my ex-t is mis firing at idle, and I'm hoping it's the spark plugs. It only said cylinder 4 when checking the cel code. I've got 24,000 miles on it, and I bought it back in February. I typically redline it every time i take it out. Anyone have any thoughts?

 

[bembol]

Just as a rule of thumb, I change mine every 2 years. I donno if MMI or Honda's schedule includes spark plugs, but $50 every 2 years isn't that bad, and relatively easy to do.

I'd think if you had a V6 with the rear bank close to the firewall (as my old V6 Accord, ugh), or worse if you have a boxer engine, then you'd avoid changing more often than necessary, but with our cars it should take less than 15 minutes for all.

Also worth looking into is if your car has a distributor, and changing out the dizzy wires if they've never been replaced. Your car may not have them, I donno.

It was so easy on my 2002 Acura RSX I changed it every 77k/km. DIY twice, my next two was & is a Nissan V6 VQ35DE and left it alone, I was told it's a PITA. Had my 2008 Altima Coupe for 190k/km and no issues and my Murano currently has 60k.

Is my FK7 easy as the RSX?

 

[peterletran]

So ... I took my cylinder 4 spark plug out, and ... the ceramic insulator next to the electrode has come loose ... I can't find this PITA sized spark plug anywhere locally. Any pointers?

 

[charleswrivers]

If your car has an off idle... poor power off the line or a gradual and consistent loss of mileage that can't be explained, it might be an inexpensive thing to try.

My mother-in-law's Galant had a rough idle with an occasional stall and was down a smidge on power and mileage and I did them early the year before last. They were iridium's and their gaps were waaay off and different across all 4. I just replaced rather than regap. I think their manual called for ~100k and I did it at 50-60k. Cured it's issue.

I'm doing my Odyssey this spring/summer. The main reason for that is it's cylinder deactivation is, IMO, causing different wear and making their gaps different. I don't find it quite as smooth during the transitions for the deactivation and less power when it's running as a 3/4 cylinder. I won't know for sure until I take them out... and by the time I go through the trouble to take them out, I'm putting new ones in. It's at about 53k and 4 years now.

Plugs are cheap. I wouldn't replace them early randomly, but if things seem... off, they're not a bad thing to short cycle when you don't see anything else wrong to try. I have gapped plugs, but after years and 10s of thousands of miles, I just replace.

I also would not let them go too long past their recommended change time if for no reason other than them getting stuck in the aluminum head.

 

[Shankmeyster]

This mighty be off topic, but my ex-t is mis firing at idle, and I'm hoping it's the spark plugs. It only said cylinder 4 when checking the cel code. I've got 24,000 miles on it, and I bought it back in February. I typically redline it every time i take it out. Anyone have any thoughts?

Just be aware, ifyour engine blows you're going to be looking at paying for a new engine. They can see if you've redlined it and that is grounds for denial of warranty. Already had one guy who had this happen because he misshifted.

 

[inv4zn]

It was so easy on my 2002 Acura RSX I changed it every 77k/km. DIY twice, my next two was & is a Nissan V6 VQ35DE and left it alone, I was told it's a PITA. Had my 2008 Altima Coupe for 190k/km and no issues and my Murano currently has 60k.

Is my FK7 easy as the RSX?

Any 4-banger with the cylinders pointing straight up will be as easy as they come. Remove coil packs, remove plugs, replace, replace.

 

[inv4zn]

I also would not let them go too long past their recommended change time if for no reason other than them getting stuck in the aluminum head.

There was a story on the internet a long time ago about who DIY'ed his spark plugs and decided adding loc-tite to the plug threads was a good idea lol

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