2018 stock V6 Stinger spark plugs recurrent early failure/replacement

[stinger123]

I have a 2018 Kia Stinger V6, completely stock with only 32000km and have had incredible difficulty resolving an ongoing recurrent issue since August of last year. The car has had intermittent issues hesitating and stuttering with acceleration with the check engine light coming on intermittently. The car has been into the dealer 5 or 6 times for this now.

Initially they "couldn't reproduce" the issue; however the check engine light eventually went on permanently and then they finally dealt with things and said there was early spark plug cracking/failure to 2 or 3 of the plugs. The car was throwing cylinder misfire codes at a few different cylinders- 2 and 4 if I remember correctly.This was at roughly 25 000km so they agreed to replace 3 of the plugs under warranty.

The issue was resolved for a few weeks but then started again, and they said a few other plugs had cracked. They replaced the 3 other plugs. Things were good for 4 or 5 months, but then the same issue started again. CEL came on and a cylinder misfire code was being thrown. They said another one of these relatively new plugs had cracked and replaced just one of them. Again, this resolved the issue for a month or two.

Just yesterday, I am having the same issue again- stuttering acceleration and intermittently CEL with acceleration. I am at wits end at this point. The dealership has not provided a clear answer as to what is causing the recurrent early spark plug failure/wear. Although replacing plugs seems to resolve things temporarily, there certainly must be some underlying issue causing this.

Has anyone else experienced anything similar in a stock Stinger or have any ideas/advice? I am at the point where I feel like giving up and just trading it in. Thank you.

 

[GetStung915]

I'm at 100,000 km with my 2018 kia stinger V6. Just barely started experiencing this. Car had been running great until recently.

 

[ht_addict]

Seeing that you are having issues with the plugs that they are supplying, see if they will reimburse you for HKS or Denso if you buy and bring them in for install.

 

[MerlintheMad]

Can spark plugs cause misfire only under load? You might find this thread of mine enlightening. At the moment, my car feels brand new again. But only time will tell if replacing the boot/coil stops sparkplug failure. I'm cautiously optimistic, since our family mechanic told me that when you have a cracked plug like that, simply putting in a new plug won't solve anything: it will just go bad, sooner rather than later: the cause being fouled boot, and you can't clean the fouling off either: you have to replace the boot when a sparkplug cracks like that. I dealt with this exact issue for a solid half a year, and this time around the dealer replaced the boot/coil.

(edit: you've already seen that thread, I see, reading back over it; but you didn't get to the recent part, where this week I had the boot/coil replaced along with the plug)

 

[stoopid]

Seeing that you are having issues with the plugs that they are supplying, see if they will reimburse you for HKS or Denso if you buy and bring them in for install.

My suggestion was going to be similar, except I would just buy the plugs if they agreed to install them (at some point I'd have to buy plugs past the warranty point anyway). At least they're dealing with installing them which is a bit of a pain on a few of the cylinders because of the engine layout.

Then I read Merlin's post, and that seems reasonable especially since the issue is coming back frequently. Better plugs may be more durable, but it would be more reasonable to replace the boot if it stops the issue altogether.

 

[cncBilly]

I have a 2018 Kia Stinger V6, completely stock with only 32000km and have had incredible difficulty resolving an ongoing recurrent issue since August of last year. The car has had intermittent issues hesitating and stuttering with acceleration with the check engine light coming on intermittently. The car has been into the dealer 5 or 6 times for this now.

Initially they "couldn't reproduce" the issue; however the check engine light eventually went on permanently and then they finally dealt with things and said there was early spark plug cracking/failure to 2 or 3 of the plugs. The car was throwing cylinder misfire codes at a few different cylinders- 2 and 4 if I remember correctly.This was at roughly 25 000km so they agreed to replace 3 of the plugs under warranty.

The issue was resolved for a few weeks but then started again, and they said a few other plugs had cracked. They replaced the 3 other plugs. Things were good for 4 or 5 months, but then the same issue started again. CEL came on and a cylinder misfire code was being thrown. They said another one of these relatively new plugs had cracked and replaced just one of them. Again, this resolved the issue for a month or two.

Just yesterday, I am having the same issue again- stuttering acceleration and intermittently CEL with acceleration. I am at wits end at this point. The dealership has not provided a clear answer as to what is causing the recurrent early spark plug failure/wear. Although replacing plugs seems to resolve things temporarily, there certainly must be some underlying issue causing this.

Has anyone else experienced anything similar in a stock Stinger or have any ideas/advice? I am at the point where I feel like giving up and just trading it in. Thank you.

I think you got all you need from the boys above. Good luck.

 

[stinger123]

It is another cracked plug. It is the 4th time that plugs have needed to be replaced from 25000 to 3300km on the odometer. The tech could not find any reason why the plugs keep failing prematurely every few thousand km. They are calling kia canada to ask for further advice. I suggested that they cover labour for aftermarket plug installation and they refused this. The tech mentioned he has seen numerous stingers with premature spark plug failure.

It frustrates me so much that this is either a design flaw or a quality issue with kia OEM spark plugs, yet they arent offering me a long lasting solution. I guess i am either stuck going to the dealership every few months to get plugs replaced once they fail (just over a year of warranty left) or am stuck paying $400-500 CDN to get aftermarket plugs and have them installed (with no guarantee this does indeed solve things).

 

[MerlintheMad]

^^^Did you talk about boot/coil replacement? Each cylinder that has failing plugs should have the boot/coil replaced (according to my mechanic, as I've already shared, the boot gets fouled/corroded, and ruins each new plug).

 

[stinger123]

Thanks for the advice, Merlinthemad. I just got another update. Kia canada told the dealership that the coils should be replaced as well. They have to order them in, so I will be without the car a few more days. Hopefully this finally solves things.

 

[MerlintheMad]

Why do you have to be without the car? Doesn't it run normally when you keep the turbo boost out of it?

Thanks for the advice, Merlinthemad. I just got another update. Kia canada told the dealership that the coils should be replaced as well. They have to order them in, so I will be without the car a few more days. Hopefully this finally solves things.

 

[SRV]

^^^Did you talk about boot/coil replacement? Each cylinder that has failing plugs should have the boot/coil replaced (according to my mechanic, as I've already shared, the boot gets fouled/corroded, and ruins each new plug).

Good to know!

 

[stinger123]

Why do you have to be without the car? Doesn't it run normally when you keep the turbo boost out of it?

They got it done today. Going to pick it up soon. Apparently 3 more plugs were discovered with excessive carbon build up so they replaced those as well as the ignition coils on the advice of Kia Canada. Would issues with the ignition coils cause carbon build up on the plugs or is there likely another underlying issue causing this? They say it runs fine now, no misfires, no codes. Nonetheless, I am going to drive the car a lot the next few weeks to see if any issues return.

 

[MerlintheMad]

They got it done today. Going to pick it up soon. Apparently 3 more plugs were discovered with excessive carbon build up so they replaced those as well as the ignition coils on the advice of Kia Canada. Would issues with the ignition coils cause carbon build up on the plugs or is there likely another underlying issue causing this? They say it runs fine now, no misfires, no codes. Nonetheless, I am going to drive the car a lot the next few weeks to see if any issues return.

"Carbon buildup" is likely what this layman (yours truly) calls corrosion or fouling. My mechanic said replace the boots whenever you have a failed/cracked plug, for that reason. On the Stinger the boot and coil come together.

 

[stinger123]

"Carbon buildup" is likely what this layman (yours truly) calls corrosion or fouling. My mechanic said replace the boots whenever you have a failed/cracked plug, for that reason. On the Stinger the boot and coil come together.

Well hopefully this fixes things then with all coils replaced. I will bump this thread if I have further issues.

 

[MerlintheMad]

Well hopefully this fixes things then with all coils replaced. I will bump this thread if I have further issues.

I've only had issues with one coil/boot. And here you've have all six replaced. What causes them to go bad in the first place? It's not as if you and I are doing something to cause this, being bone stock as we are.

 

[Bluestinger1607]

I am experiencing the exact same story rn. They replaced the coils already 4 months later now im at the dealer ship with the same problems

 

[MerlintheMad]

I am experiencing the exact same story rn. They replaced the coils already 4 months later now im at the dealer ship with the same problems

Welcome. Are you stock? Modding the drivetrain can cause the potential for complications.

 

[stinger123]

Since they did all 6 coils and all 6 plugs earlier this year, mine has been good. I haven't driven too much since then though, maybe just a few thousand km.

 

[Kazz]

Dealing with this myself. Replaced plugs with properly-gapped Densos. None were cracked. Problem persisted. Intermittent check engine light that read as P0300, random misfire. Dealership got 3 coils to do some troubleshooting. Replaced 3 coils. Swear I still have intermittent hesitation under boosted acceleration but not getting any codes. Hoping to get more codes so I can get the other 3 replaced. Why doesn't the hesitation create codes? If it's not the spark plugs or coils then its in power delivery like the transmission...

 

[SRV]

Prior to getting my awesome Stinger, I've never heard of cracked coils and their ramifications, so I did some Googling and came across this, the interesting part starts at 20 seconds:

Now I understand why the engine will not run properly.

Here's another one: