100k miles, Should I change my Spark Plugs?

[Noo]

I have a 2005 Accord V6 Hybrid with 200k miles, according to maintenance records, the plugs were last changed at around 100k miles. It uses those Iridium type spark plugs that supposed to last 100k miles. I pulled the plugs the other day to measure tolerance & check its condition and everything looks good & within spec as far as gap.

I'm not sure if changing spark plugs is necessary and a must do regardless of the car's performance OR you only change it when it goes bad.

Right now, the car runs perfect when warmed or warmed up. However, in cold such as 32 degrees morning, I can feel the car have more vibration from the engine.

Not sure if that's even a spark plug issue, considering it's have 200k miles it probably need valve adjustment or due to all the wear and tear in the engine internal.

 

[RLGL]

If it ain't broke don't fix it , comes to mind. Change the plugs according to the owners manual schedule

 

[Noo]

If it ain't broke don't fix it , comes to mind. Change the plugs according to the owners manual schedule

That's a conflicting statement.

 

[PottedMeat]

That's a conflicting statement.

...it's completely up to you. toss a coin. you said yourself the plugs look fine and probably aren't the issue. if you're going to be doing a bunch of other stuff in there anyway what's another $60?

 

[mindless1]

Did you pull and check ALL plugs? One plug isn't an indicator of the rest.

Yes if they look good you can keep using them, one of the main things is don't leave them in too much over 100K if even that as they can become seized in. Merely removing and inspecting the threads will handle that.

However once I have gone to the trouble of pulling them all, I go ahead and change them, and put a new set of wires on too... sometimes the mere act of pulling old wires will cause a fault, so for the few dozen dollars I'll just replace them, not with overpriced OEM wires which have nothing magical about them to justify the high price. Just don't buy junk.

Another thing I'd do at 200K/300K/etc while I have the plugs out anyway is do a compression test to get an idea of how the engine is doing.

 

[Bartman39]

Uh change the plugs 100k miles on a set is the limit... I recently changed a set in my mothers 2013 F150 with 118k miles on it and it ran like crap till I put a set of new plugs in it... Like I told her when it gets to 200k lets put another new set in it...

Just do it and forget it...

 

[tweakmonkey]

What do they cost? Clearly yours have some wear by now.

 

[dave_the_nerd]

That's a conflicting statement.

No it's not. The manual, with its recommended 100k spark plug replacement interval, is what's "not broke." You replaced 'em at 100k, so replace 'em at 200k, following the pattern.

IMO, if you're going to go to the trouble of checking them, you might as well have replaced them all anyways.

I'm lazy, and spark plugs are cheap.

 

[Torn Mind]

I highly doubt there's any shiny metal left on that spark plug, but if you don't see sings of "melting" with black spots, you probably can run 'em another 15k before checking them again.
Unless there's some new material, iridium is the metal used in a lot of long-life spark plugs.

Since your vehicle is a hybrid though, you can consider the point that the engine on a hybrid is not running all the time like it does on a regular ICE system. So, it might not actually have 100k of wear compared to a straight ICE vehicle and can go 30,000 miles, perhaps.

 

[Torn Mind]

No it's not. The manual, with its recommended 100k spark plug replacement interval, is what's "not broke." You replaced 'em at 100k, so replace 'em at 200k, following the pattern.

IMO, if you're going to go to the trouble of checking them, you might as well have replaced them all anyways.

I'm lazy, and spark plugs are cheap.

Iridium plugs are not that cheap. 6 of them at $8 or $9 a piece becomes approximately $50. Plus, keep in mind that a 200k vehicle is going to be bound to the scrapyard at some point in the near(er) future.

 

[dave_the_nerd]

Iridium plugs are not that cheap. 6 of them at $8 or $9 a piece becomes approximately $50.

That's not super-expensive. It is a car repair, after all.

Plus, keep in mind that a 200k vehicle is going to be bound to the scrapyard at some point in the near(er) future.

Yeaaaahhhh....

I can see your point, but it's an '05. It's a Honda. He's putting ~17k/year on it. It'll probably make it another 5 years at least before it's scrapyard-worthy. If he knew he was going to scrap it in 60k or less, then he could cheap out and put platinum plugs in it instead. But if he does send it to a salvage yard, in all likelihood some wag will pull then engine and transmission and get another 100k+ out of them.

 

[Torn Mind]

That's not super-expensive. It is a car repair, after all.



Yeaaaahhhh....

I can see your point, but it's an '05. It's a Honda. He's putting ~17k/year on it. It'll probably make it another 5 years at least before it's scrapyard-worthy. If he knew he was going to scrap it in 60k or less, then he could cheap out and put platinum plugs in it instead. But if he does send it to a salvage yard, in all likelihood some wag will pull then engine and transmission and get another 100k+ out of them.

Yes, it is relatively cheap for a car repair, but at the same time, these plugs likely haven't been used to the fullest yet due to the hybrid system "resting" the engine more. It makes sense to use these plugs till they show some signs that they must go, like black marks on the metal. Since it is a hybrid, there is also the consideration that the battery pack might go belly up and the more time passes, the more likely it is to do so. 50 bucks is 50 bucks. Quite a few nice things you can buy with that.

I wasn't explicit, but 5 years was what I was thinking as well. Hence, the "near(er)". At least at some point, it's due for another suspension renewal as well, like struts, ball joints, etc.

 

[KIAman]

$50 is expensive regarding a car maintenance item? I would change it especially if you can easily do it yourself.

 

[Thump553]

Is there any car these days where changing the plugs qualifies as easy? I'm semi-fortunate because the engine doesn't have to be hoisted out to change the plugs on my car.

 

[Bartman39]

$50 every 100k miles is not much... Heck it cost me a bit over $100 for oil changes (10qts. Royal Purple and a $10 filter) that is every 7500-10k miles too... No plugs but my truck now has 216K miles on it and still runs great and should till it hits about 500k miles...? Diesel...

 

[dave_the_nerd]

Is there any car these days where changing the plugs qualifies as easy? I'm semi-fortunate because the engine doesn't have to be hoisted out to change the plugs on my car.

Most Inline-4 engines have them right on top, and they're fairly easy. It's the V-whatever engines where one bank is sometimes under/behind something important that also has to be removed.

I think the Honda Accord V6 is fairly easy to get to both sides, though.

 

[dave_the_nerd]

Oh, and Advanced Auto Parts has a 30% coupon code floating around the internet right now.

 

[mindless1]

It doesn't even have to be $50 if you're that strapped for cash. "Most" vehicles run fine on single platinum. Last car I did where I didn't plan to own it past the spark plug change, I put in NGK single platinum from Advance Auto, came out to $2 each after a coupon code (other items on order bumped it up to a good coupon level).

 

[mindless1]

Most Inline-4 engines have them right on top, and they're fairly easy. It's the V-whatever engines where one bank is sometimes under/behind something important that also has to be removed.

I think the Honda Accord V6 is fairly easy to get to both sides, though.

Some V-engines require taking the intake manifold off or other misc. things and some *require* (it's a lot easier if) taking the wheels and wheel well liners out to get to it from the side, especially on RWD / longitudinal engines.

 

[Noo]

The reason I'm asking is because with the car having 206k miles in mind and is on the ORIGINAL hybrid battery, I'm not sure if it's worth putting any money into it anymore. On top of that, the car runs fine other than having a little vibration when it's freezing out (smooth when warmed up) and the plugs looks good still and is within gap specification. Not sure if it's worth spending $60+ for new plugs (the car uses coil pack so there's no need for plug wires).

 

[dave_the_nerd]

The reason I'm asking is because with the car having 206k miles in mind and is on the ORIGINAL hybrid battery, I'm not sure if it's worth putting any money into it anymore. On top of that, the car runs fine other than having a little vibration when it's freezing out (smooth when warmed up) and the plugs looks good still and is within gap specification. Not sure if it's worth spending $60+ for new plugs (the car uses coil pack so there's no need for plug wires).

My parents have a 2006 Prius w/ 340k on it. Runs like a top and the batteries "health" is still ~85%. Hybrid batteries, across the board, are lasting a lot longer than folks thought they would.

Additionally, aftermarket or remanufactured battery packs are available, which makes battery replacement a potential expense on par with a transmission swap or major engine repairs - not cheap, but something that some people choose to do, and some don't.

It's one thing if you've declared "I, Noo, am going to ditch this car when it hits 250k miles" or "I, Noo, am henceforth putting NO money into this vehicle, and when it stops running, it stops running." Hell, at that point, you can second-guess the financial logic of doing freaking oil changes.

But if you don't have an end date in mind, then doing regular maintenance, IMO, makes as much sense as it ever did. (It's insurance, to help prevent a really bad failure at a really bad time.)

 

[mindless1]

It is not a contest within which we win if we convince you to change your plugs. If you don't want to do it, don't. The thing is that if you do plan on selling it at some point and want more than beater money out of it, it helps to have (honest) records that you kept up with maintenance.

The other issue is your ability to troubleshoot down the road. If an old plug cause a misfire will you be able to diagnose it? If so, great, but if not, putting new plugs in delays if/when you'd ever need to make that diagnosis. Anyone can just run plugs until it causes a problem.

Also note that if your engine has a small % of misfires, it may not be enough to trip the check engine light but may gradually wear out catalytic converter(s) and could hurt fuel economy. However your cold engine roughness might have nothing to do with the plugs, could be an intake manifold leak, weak coil, or something along those lines.

 

[Torn Mind]

When visual evidence is bad enough that the plugs need changing, that's when he should change them. Post 200k miles is indeed the "zombie" part of a car's lifespan. It's a balancing act to keep the essentials functional but still milk the parts for all their worth and not burn money on the vehicle needlessly. Do inspections on the plugs every 6 months or something.

I guess a reasonable point to aim for is to keep the vehicle in working shape until the suspension starts dying or the emissions system starts tossing out codes. Sometimes suspensions can be quite resilient depending on road conditions though, so it might be a while.

 

[Pacfanweb]

$50 is expensive regarding a car maintenance item? I would change it especially if you can easily do it yourself.

I wouldn't. Wait until you get a miss.
I ran the 100k plug in my Suburban 180k with on drop in performance or mileage before I finally replaced them, and even then I only did it because a wire went bad and made it miss.
On most cars, those long-life plugs will go WAY over the 100k interval.

Keep 'em until you either feel a miss or get a code and a chicken light.