# Carbon build-up on valves



## ltlebug (Jan 12, 2012)

Has anyone else experienced this yet? On Monday, my check engine light was flashing for a couple of minutes, but then it stopped. I took it to the dealer, who had the car overnight to get it to misfire. It did misfire, but says that the coils and spark plugs are not the issue. Suspects the issue is carbon build-up on the valves. Thus, the intake must be removed to check it (a cost of over $400!). Of course, this being a maintenance issue, it is not covered under warranty. I only have 35,914 miles on the car and use the high grade gas for each fill-up. In my previous beetle (1.8t), I did not have a carbon build-up issue till way past 100,000 miles. I am asking to see if this is common for the 2.0t engine to have build-up issues with lower mileage. Any feed back is appreciated! 

Thank you!


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## GTarr (May 17, 2012)

Man, that is not good to hear. Carbon buildup is one of the things that worries me in the back of my mind about this car. Of course, you should get a second opinion.... Also, you should be able to do a somewhat cursory examination by removing the intake air temperature sensor and sticking a borescope in through the hole. There are cheap (~$20) USB borescope cameras available on amazon. I've been thinking of doing this myself.

GTarr


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## MKV Aaron (Oct 18, 2007)

ltlebug said:


> Has anyone else experienced this yet? On Monday, my check engine light was flashing for a couple of minutes, but then it stopped. I took it to the dealer, who had the car overnight to get it to misfire. It did misfire, but says that the coils and spark plugs are not the issue. Suspects the issue is carbon build-up on the valves. Thus, the intake must be removed to check it (a cost of over $400!). Of course, this being a maintenance issue, it is not covered under warranty. I only have 35,914 miles on the car and use the high grade gas for each fill-up. In my previous beetle (1.8t), I did not have a carbon build-up issue till way past 100,000 miles. I am asking to see if this is common for the 2.0t engine to have build-up issues with lower mileage. Any feed back is appreciated!
> 
> Thank you!


It is common however not usually this early. If you have a check engine light and misfires its not a maint issue. Push the dealer and vwoa to fix under warranty.

I'd ask to know what the cel code was.


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## drtechy (Jun 3, 2009)

Very common because it is direct injection and has the valve oil weeping system. Nothing you can do to prevent it. Like others said though I highly doubt you having that issue this early, especially if you had a CEL. I would honestly look for a second opinion


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## ltlebug (Jan 12, 2012)

GTarr said:


> Man, that is not good to hear. Carbon buildup is one of the things that worries me in the back of my mind about this car. Of course, you should get a second opinion.... Also, you should be able to do a somewhat cursory examination by removing the intake air temperature sensor and sticking a borescope in through the hole. There are cheap (~$20) USB borescope cameras available on amazon. I've been thinking of doing this myself.
> 
> GTarr


I am looking right now in obtaining a borescope..gotta love amazon  I have dealt with this dealer for over 10 years, and they have been honest with me in the past and have worked with me on warranty issues before. So I think they are honest. But being able to personally verify is the best policy...hence the emergency shopping now for a borescope  Thank you GTarr! 



MKV Aaron said:


> It is common however not usually this early. If you have a check engine light and misfires its not a maint issue. Push the dealer and vwoa to fix under warranty.
> 
> I'd ask to know what the cel code was.


I already made a call to VOA and started a case on it. A case manager is supposed to contact me by Friday end of day, however, they said they cannot really do anything until a full diagnosis is complete. Thus, i need to pay for the intake to be removed. I asked that they contact the dealer as well, maybe he can explain it more to them without the additional $400 expense! Great advice on getting the cel code. I will get that as soon as possible. Thank you MKV Aaron!


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## ltlebug (Jan 12, 2012)

drtechy said:


> Very common because it is direct injection and has the valve oil weeping system. Nothing you can do to prevent it. Like others said though I highly doubt you having that issue this early, especially if you had a CEL. I would honestly look for a second opinion


This is what surprised me, that the issue was this early on. I think with two now suggesting a second opinion and even though I trust this long-time dealer, i am going to get a second opinion. Thank you for your feedback Drtechy. BTW, good job on finding the culplrit behind your rev issue


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## ltlebug (Jan 12, 2012)

*Update*

Thank you Gtarr for suggesting the use of borescope, since the dealer had one and there is definitely carbon build-up on the intake valves. The fault codes that registered were: P0300 & P0302. I have no idea what the codes mean, but I am sure many of you do. This is the beginning of many future expenses (~$800 total for this one with this dealer. I probably should shop around for a better price, but just can't do it since I am picky as to whom I hand my car to).


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## drtechy (Jun 3, 2009)

ltlebug said:


> Thank you Gtarr for suggesting the use of borescope, since the dealer had one and there is definitely carbon build-up on the intake valves. The fault codes that registered were: P0300 & P0302. I have no idea what the codes mean, but I am sure many of you do. This is the beginning of many future expenses (~$800 total for this one with this dealer. I probably should shop around for a better price, but just can't do it since I am picky as to whom I hand my car to).


Just so you know those codes do not point to anything particular in regards to carbon build up. They are simply misfire codes. Personally I would rather them swap coil packs and spark plugs around to see if the misfire moves. That's a lot of money to throw at a problem with knowing for sure that carbon buildup is the issue, unless they are willing to offer a guarantee that it will solve the issue, but i doubt they would.


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## MKV Aaron (Oct 18, 2007)

A few things.

The codes are for cylinder misfires. I'd put my money on it being the spark plugs. If it were my car, I'd do the following:

Take coils from the misfired cylinders and swap them to the "good" cylinders. Clear the codes, and redrive. If the codes follow the "bad" coils, you know its the coils. If it stays the same, replace the spark plugs.

As far as the carbon goes, yes it will have some carbon on the valves. Should it be enough to cause your issues? No.

Like I said before, there is NO way you should be charged a dime for this, even if it was carbon related, due to no maintenance interval being missed on your end (plugs are something like 40 or 60k, and coils are never). I understand you have to OK the removal, but after they find carbon, its on their dime.

On my stg 2 TSI GTI, I had a misfire on 1 cylinder, did the above, it was a single bad coil. $15, off on my way. PS, mine had 78k HARD miles, and only had the intake manifold need replaced.


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## drtechy (Jun 3, 2009)

MKV Aaron said:


> A few things.
> 
> The codes are for cylinder misfires. I'd put my money on it being the spark plugs. If it were my car, I'd do the following:
> 
> ...


He^^^ said it better than I did lol


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## MKV Aaron (Oct 18, 2007)

drtechy said:


> Just so you know those codes do not point to anything particular in regards to carbon build up. They are simply misfire codes. Personally I would rather them swap coil packs and spark plugs around to see if the misfire moves. That's a lot of money to throw at a problem with knowing for sure that carbon buildup is the issue, unless they are willing to offer a guarantee that it will solve the issue, but i doubt they would.


Great minds think alike. I'd bet money its plugs or coils.


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## ltlebug (Jan 12, 2012)

drtechy said:


> Just so you know those codes do not point to anything particular in regards to carbon build up. They are simply misfire codes. Personally I would rather them swap coil packs and spark plugs around to see if the misfire moves. That's a lot of money to throw at a problem with knowing for sure that carbon buildup is the issue, unless they are willing to offer a guarantee that it will solve the issue, but i doubt they would.





MKV Aaron said:


> A few things.
> 
> The codes are for cylinder misfires. I'd put my money on it being the spark plugs. If it were my car, I'd do the following:
> 
> ...


You two are just too funny!  You both kick a$$! I told the dealer he can keep the car till Friday until I make an informed decision on the next step. As before, thank you so much for your input and feedback, which I am taking to heart. Much appreciated! All this information is really going to be extra beneficial when VOA calls me on Friday and I can lay things out. The dealer and VOA need to work this out.


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## drtechy (Jun 3, 2009)

ltlebug said:


> You two are just too funny!  You both kick a$$! I told the dealer he can keep the car till Friday until I make an informed decision on the next step. As before, thank you so much for your input and feedback, which I am taking to heart. Much appreciated! All this information is really going to be extra beneficial when VOA calls me on Friday and I can lay things out. The dealer and VOA need to work this out.


No problem, my first question to the dealer/tech would be "How do you know its not the coil packs or spark plugs?" You can't rule that out unless they swapped them around to see. Now if they did do that and they still say it isn't those well I wouldn't know exactly where to go next, but carbon buildup would definitely not be next on the list. Good luck and keep us posted, and remember if they really want to do the carbon cleanup for $800 you're going to want a guarantee because that's stupid money to pay for something like that when they don't know for sure it will fix the issue.


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## ltlebug (Jan 12, 2012)

drtechy said:


> No problem, my first question to the dealer/tech would be "How do you know its not the coil packs or spark plugs?" You can't rule that out unless they swapped them around to see. Now if they did do that and they still say it isn't those well I wouldn't know exactly where to go next, but carbon buildup would definitely not be next on the list. Good luck and keep us posted, and remember if they really want to do the carbon cleanup for $800 you're going to want a guarantee because that's stupid money to pay for something like that when they don't know for sure it will fix the issue.


Yes Dr.!


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## PooLeArMor (Aug 13, 2008)

how do u drive ur car ??
if you always drive like u stole it, Carbon build-up wont show up that early,,,

the best way to avoid getting less Carbon build-up early is do a kick down the throttle once in a while on the highway.


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## ridgemanron (Sep 27, 2011)

PooLeArMor said:


> how do u drive ur car ??
> if you always drive like u stole it, Carbon build-up wont show up that early,,,
> 
> the best way to avoid getting less Carbon build-up early is do a kick down the throttle once in a while on the highway.


'The Car Doctor', Ron Ananian (on the radio) swears by the gas additive Techron 
by Chevron, claiming he sees excellent results with regard to customers cars over time. If
you have access to Chevron gasoline stations, you get it 'free' in their gas. Otherwise, you have
to buy it at places like Pep Boys. There are no Chevron stations in my area, and though I read that
Texaco is another Chevron related operation, they too are nowhere to be found in Brooklyn.


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## MKV Aaron (Oct 18, 2007)

ridgemanron said:


> 'The Car Doctor', Ron Ananian (on the radio) swears by the gas additive Techron
> by Chevron, claiming he sees excellent results with regard to customers cars over time. If
> you have access to Chevron gasoline stations, you get it 'free' in their gas. Otherwise, you have
> to buy it at places like Pep Boys. There are no Chevron stations in my area, and though I read that
> Texaco is another Chevron related operation, they too are nowhere to be found in Brooklyn.


Gas doesn't touch the stems of the valves on a direct injection vehicle, so no amount of detergents in the gas will prevent carbon buildup.


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## MKV Aaron (Oct 18, 2007)

PooLeArMor said:


> how do u drive ur car ??
> if you always drive like u stole it, Carbon build-up wont show up that early,,,
> 
> the best way to avoid getting less Carbon build-up early is do a kick down the throttle once in a while on the highway.


Agreed. Everyone has carbon buildup, its just a matter of how much and how long it'll take to affect driveability. Its thought to help to drive the car hard to slow carbon buildup.


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## ridgemanron (Sep 27, 2011)

MKV Aaron said:


> Agreed. Everyone has carbon buildup, its just a matter of how much and how long it'll take to affect driveability. Its thought to help to drive the car hard to slow carbon buildup.


I remember some time back that there was a machine that you could hook-up and remove carbon from some cars.


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## drtechy (Jun 3, 2009)

ridgemanron said:


> I remember some time back that there was a machine that you could hook-up and remove carbon from some cars.


I've seen people use media blasters with walnut shells as the media, but you still have to remove the intake manifold to do so.

posted by tapatalk


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## MKV Aaron (Oct 18, 2007)

ridgemanron said:


> I remember some time back that there was a machine that you could hook-up and remove carbon from some cars.


BMW has a special de carboning tool for their engines. That is because they chose to acknowledge an issue with carbon, where VW/Audi act like it doesn't happen lol.


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## ltlebug (Jan 12, 2012)

PooLeArMor said:


> how do u drive ur car ??
> if you always drive like u stole it, Carbon build-up wont show up that early,,,
> 
> the best way to avoid getting less Carbon build-up early is do a kick down the throttle once in a while on the highway.





MKV Aaron said:


> Agreed. Everyone has carbon buildup, its just a matter of how much and how long it'll take to affect driveability. Its thought to help to drive the car hard to slow carbon buildup.





drtechy said:


> No problem, my first question to the dealer/tech would be "How do you know its not the coil packs or spark plugs?" You can't rule that out unless they swapped them around to see. Now if they did do that and they still say it isn't those well I wouldn't know exactly where to go next, but carbon buildup would definitely not be next on the list. Good luck and keep us posted, and remember if they really want to do the carbon cleanup for $800 you're going to want a guarantee because that's stupid money to pay for something like that when they don't know for sure it will fix the issue.


I do drive my car hard, where most of my driving is highway, and I do speed and like to drive past cars, hence my nickname "speedy", and why I have a 6MT turbo beetle  I went to the dealer early this a.m. and told him to switch spark plugs and coils around and make sure code still shows faults in same place. He told me he did that and is certain issue is carbon build-up. Around 11 a.m. VoA contacted the dealer and got info from him. VoA has stepped up! According to them, this one time good will deal is because of my VW loyalty, where I have only owned beetles as my cars and have been a VW customer since 2002, they are paying 75% of cost. Hopefully this is just a fluke and I will not have to clean my intake every 36,000 miles! I am very please VoA stepped up and very happy with this one time offer of paying 75% of cost.


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## drtechy (Jun 3, 2009)

I hope it fixes it, did they happen to mention if you still have to pay if it doesn't though?

posted by tapatalk


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## ltlebug (Jan 12, 2012)

ridgemanron said:


> 'The Car Doctor', Ron Ananian (on the radio) swears by the gas additive Techron
> by Chevron, claiming he sees excellent results with regard to customers cars over time. If
> you have access to Chevron gasoline stations, you get it 'free' in their gas. Otherwise, you have
> to buy it at places like Pep Boys. There are no Chevron stations in my area, and though I read that
> Texaco is another Chevron related operation, they too are nowhere to be found in Brooklyn.


According to VoA, Chevron and Shell are on this top tier list they have. They did suggest that i use an additive to fuel. Did not tell me which brand, and said that the service personnel at dealer will be more knowledgeable as to which is best for my car.


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## ltlebug (Jan 12, 2012)

drtechy said:


> I hope it fixes it, did they happen to mention if you still have to pay if it doesn't though?
> 
> posted by tapatalk


I hope so too. They didn't say anything about that, since dealer is certain this is the issue. But based on my previous experience, I think VW will fix under warranty if problem turns out to be because of a warranty item. I alerted to the issue prior to warranty expiring and they okay'd this repair as being the fix. So if for some reason issue is something else, I cant really see them having a leg to stand on in denying it. Of course, they have done that to others and they can just simply say no. But for now, I just have to have faith in that dealer did everything to make sure carbon is the issue and eliminated everything else. I have dealt with this dealer since 02 and they know me....i love my cars and I am overly protective and now know I have knowledgeable people like you, explaining things to me and suggesting other options or issues. So lets hope this scared them to do a good job  Thanks again for all your input...very helpful!!!


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