Change oil early after fixed misfire? Elantra 2.0

Joined
Feb 19, 2009
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720
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Upstate, NY
Hey question on what my next step should be with my 09 Elantra with the 2.0L. Background:
I had a very slight misfire for about 1200 miles on this oc of m1 ep 5w20, that would only feel noticeable on cold starts shortly or under 1500 Rpms when warm with very light throttle input. I replaced spark plugs (NGK), air filter(fram ultra) and cleaned maf and even changed the transmission fluid… 3 times with no change and just “assumed” this motor was not a smooth motor. 🔧 I still got over 32 mpg on highway, and never a check engine light. But fast forward 1200 miles and a month later I wanted to change the spark plug wires because that was one component I did not change as I again “assumed” the wires have been changed out with Hyundai oem wires at some point. I was wrong! They must of been the original wires from 2009 with 115k on them because the new premium wires I installed made the engine silky smooth, better throttle response, and no more slight shudder at 1500 rpms and under. It even starts a lot easier now when cold… the throttle response feels great and it pulls alot better lower in the rpm range without need for down shifts! It even redlines faster so the old wires were shot and long over due. 😩
The question is should I change out the oil? It does smell of gas 😮 but never raised on the dip stick. Would the gas in the oil evaporate and I’ll be okay or am I doing engine damage and should change out ASAP? This again was not a “hard” misfire with a check engine light but it felt like more so like a incomplete spark or half strength spark misfire if that makes sense. Now that it’s running correctly I noticed it’s again a lot smoother almost Honda smooth haha.
Let me know what you think, thanks in advanced 🙌
 

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I’d personally change it just for the peace of mind; especially if you smell I burned fuel in your oil. With the current rebates on Mobil1 you could drop that oil and replace it for around $10 for another jug of that same oil. Couldn’t hurt to change out the filter as well.
 

09 GLS

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I just hooked up code reader no pending misfire codes, or any other codes with all values set to ready and "pass".
Thanks for informing me of the rebates on m1. I for some reason overlooked that part, and did not even know they had rebates going on :D
 
Joined
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Upper midwest
Hey question on what my next step should be with my 09 Elantra with the 2.0L. Background:
I had a very slight misfire for about 1200 miles on this oc of m1 ep 5w20, that would only feel noticeable on cold starts shortly or under 1500 Rpms when warm with very light throttle input. I replaced spark plugs (NGK), air filter(fram ultra) and cleaned maf and even changed the transmission fluid… 3 times with no change and just “assumed” this motor was not a smooth motor. 🔧 I still got over 32 mpg on highway, and never a check engine light. But fast forward 1200 miles and a month later I wanted to change the spark plug wires because that was one component I did not change as I again “assumed” the wires have been changed out with Hyundai oem wires at some point. I was wrong! They must of been the original wires from 2009 with 115k on them because the new premium wires I installed made the engine silky smooth, better throttle response, and no more slight shudder at 1500 rpms and under. It even starts a lot easier now when cold… the throttle response feels great and it pulls alot better lower in the rpm range without need for down shifts! It even redlines faster so the old wires were shot and long over due. 😩
The question is should I change out the oil? It does smell of gas 😮 but never raised on the dip stick. Would the gas in the oil evaporate and I’ll be okay or am I doing engine damage and should change out ASAP? This again was not a “hard” misfire with a check engine light but it felt like more so like a incomplete spark or half strength spark misfire if that makes sense. Now that it’s running correctly I noticed it’s again a lot smoother almost Honda smooth haha.
Let me know what you think, thanks in advanced 🙌
Do not dump your oil, there is ZERO need to. My Hyundai 2018 Kona 1.6T GDI turbo tuner car was running over 5% fuel dilution for most of it's life. I knew when I bought it new I going to have that. I bought a pre paid 10 pack of oil testing bottles and have been watching it for 27,000 miles for engine wear. I have not had any with the exception of switching oil too fast and getting an add pack lead spike. Fuel dilution is basically a non-issue that too many who have it get all out of shape and if you work through it through testing you know it turns out to be a total non-issue. I have gained as much as 3/4 of a qt of fuel in the winter months with short tripping 10 miles to work, -10 to -20 degs in the winter and I ALWAYS let my car warm up winter or summer for at least 3-4 minutes to let the pistons expand as I am on boost more then most and I don't want piston wear from non- expanded pistons and high piston/ring load. I am the worsted case scenario on fuel dilution and I always test out with no wear issues.
 
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I would be more concerned with the catalytic converter(s) after a misfire than I would be the engine oil. Oil is cheap, though. Change it if it helps you sleep better.
 
Joined
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A misfire is just that. No spark sometimes when there should have been one. Likely the old wires has a pinhole that was arcing the spark to chassis before it went into the plug. A agree with the above statement, run a normal OCI. no need for an early change.
 
Joined
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When it doubt change it out, or have it tested first. No harm in changing the oil, you had a misfire for ~ 1,200 miles. You had no idea how much fuel if any was in the oil, since you didn't have the oil tested imo you did the right thing. Time to hide. hide
 
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I owned a 2012 Elantra Touring, with the same motor, purchased brand new, and traded in at 300k miles.

It did not burn a drop of oil, even on a lifetime of thinnest 0W20 and hard driving.

You have a renowned engine, one that is very durable.

Change the oil to ensure long life.

Change the timing belt and ALL associated hardware on the 100k miles.

At 50 k mile intervals, change the transmission fluid with OEM SP III or exact Eneos fluid from NAPA.

Eventually, give this car to your grandchild !

Hope this helps.
 

09 GLS

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Joined
Feb 19, 2009
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Upstate, NY
Thank you for all the suggestions! I think i will run it a little while then change it out for piece of mind.:unsure:
I owned a 2012 Elantra Touring, with the same motor, purchased brand new, and traded in at 300k miles.

It did not burn a drop of oil, even on a lifetime of thinnest 0W20 and hard driving.

You have a renowned engine, one that is very durable.

Change the oil to ensure long life.

Change the timing belt and ALL associated hardware on the 100k miles.

At 50 k mile intervals, change the transmission fluid with OEM SP III or exact Eneos fluid from NAPA.

Eventually, give this car to your grandchild !

Hope this helps.
This is really encouraging! I like you do not burn any oil, using 5W20 and hard-ish driving. I will be doing 5-6k OCI with this engine. Timing belt and all hardware was changed out at 87K miles in 2018, so i should be good there for a few more years. I also plan to do 30K transmission fluid changes because it cheap insurance. I already did a 3X3 to get it up to par, but fluid was red already and serviced in the past, just not by me lol. Transmission shifts beautifully. Coolant is genuine Hyundai, and also has been serviced and full, but i think i will have a brake fluid flush done because while it is clear, i dont know when the last time it was serviced. Brake feel is fantastic esp with the upgraded powerstops drilled/slotted with Z23 Evolution pads. No vibration, and will activate ABS with just a jab of your big toe!. Is there anything else i should "address" or common failure points on this Elantra? I see it has a in tank fuel filter, worth replacing? I don't have any fuel delivery issues, and do use 91 ethanol free with MMO in the tank at every fill up. I know some agree, and some say its a waste, but i really believe it helps more then it hurts, as it cleans the fuel lines/injectors/upper cylinder lubricant/fuel pump lubricant.
When it doubt change it out, or have it tested first. No harm in changing the oil, you had a misfire for ~ 1,200 miles. You had no idea how much fuel if any was in the oil, since you didn't have the oil tested imo you did the right thing. Time to hide. hide
This is my thinking cheap insurance. I was "try" to run it a little longer, but probably will change it out sooner then later.😜
Good work on replacing the wires and getting your car running smooth again! I would run the oil for your normal oci
I'm working on it! 🙃 Thanks!. I can not believe i overlooked the wires, as i read this engine is not a honda type smooth but super reliable, so i just assumed it was "ruff". It really does feel like a new engine now that its not misfiring, and even has more power. Here's hoping for 35+ MPG on highway.
IMG_1783.jpeg

I would be more concerned with the catalytic converter(s) after a misfire than I would be the engine oil. Oil is cheap, though. Change it if it helps you sleep better.
I thought about the cat, and i think they are okay as i believe i addressed the misfire(s) soon enough.. It never appeared to overheat or anything, and never made that cracking sound when i turned off the car, even the engine compartment was never "burning hot". I wish didn't run it as long as i did, but it was so slight under certain conditions, that i did not even think anything was wrong, until i fixed it... :oops:
I’d personally change it just for the peace of mind; especially if you smell I burned fuel in your oil. With the current rebates on Mobil1 you could drop that oil and replace it for around $10 for another jug of that same oil. Couldn’t hurt to change out the filter as well.
I like your thinking! I very well might change it out, and do a rebate and i'm out 10$ but have a piece of mind!.

Thanks again everyone!
 
Joined
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Martinsburg West Virginia
These are known to leave the oil smelling like fuel, excellent engines though. Mine smells like fuel not too long after the oil change and not much worse when it is getting replaced. My friend has a car with this engine and his does the exact same thing.

I also changed my plugs and wires and it did smooth out a bit. This is an old engine and not as refined as some are these days. On the other hand I appreciate the simplicity of not having drive by wire throttle on my 2010. I also didn't mind when it got 40 MPG on a trip to Florida. Mine has different gearing because it is a BLUE model which is manual only. Take good care of it and you will have it a long time.

As for the timing belt replacement, make sure it says on your receipt what was replaced. Hyundai dealer actually just does the belt on timing belt replacements. I didn't trust that and took mine apart when I bought it earlier this year. I am glad that I did because the tensioner bearing was okay, but the bearing in the idler pulley was bad. Had I left it, it would have seized and we know what happens then. Would hate to kill an engine with only 54k on it.
 
Joined
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These are known to leave the oil smelling like fuel, excellent engines though. Mine smells like fuel not too long after the oil change and not much worse when it is getting replaced. My friend has a car with this engine and his does the exact same thing.

I also changed my plugs and wires and it did smooth out a bit. This is an old engine and not as refined as some are these days. On the other hand I appreciate the simplicity of not having drive by wire throttle on my 2010. I also didn't mind when it got 40 MPG on a trip to Florida. Mine has different gearing because it is a BLUE model which is manual only. Take good care of it and you will have it a long time.

As for the timing belt replacement, make sure it says on your receipt what was replaced. Hyundai dealer actually just does the belt on timing belt replacements. I didn't trust that and took mine apart when I bought it earlier this year. I am glad that I did because the tensioner bearing was okay, but the bearing in the idler pulley was bad. Had I left it, it would have seized and we know what happens then. Would hate to kill an engine with only 54k on it.
I had similar experiences. My mechanic showed me the scuffing on the old tensioner surface. It was about to go. Change all associated hardware with the timing belt.
 
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