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Carbon Buildup 101

MyGTI812

Passed Driver's Ed
Unfortunately it seems like this is just one of those things we have to deal with with our GTIs. I was fortunate enough when I had mine done the intake manifold was causing the CEL so much of the labor was covered under warranty because basically removing that is most of the labor. Something to keep in mind.

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FriggenT1

Banned
Yea I thought that quote was outrageous. And Ive got a couple vw shops in mind that I will call Monday but thought maybe there's something less invasive I could do to potentially get rid of the buildup. The guy at the dealer said it being at 50k miles it probably shouldn't be that thick

That guy doesn't know what he's talking about then, some 30k cars have horrible build up, it simply depends on driving habits, gas quality can have a small effect, oil changes going too long possibly, etc.
 
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hbrown0509

Go Kart Champion
That guy doesn't know what he's talking about then, some 30k cars have horrible build up, it simply depends on driving habits, gas quality can have a small effect, oil changes going too long possibly, etc.



Yeah I never fully trust what dealership service agents tell me. I had mine recommended for the induction cleaning and fuel injector cleaning but at $400 and almost 30k miles and rather wait and use that money towards a manual cleaning lol. Dealerships can rob you of your hard earned cash and offer really no benefit.


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DasAuto12

Passed Driver's Ed
So I was driving just now and the check engine light is off I noticed. I know the Italian tune might just be placebo but I did that for about 20 mins yesterday and idk if that helped or not but the light is off. But then, I'm looking at the work order they quoted me and I see that the tech "suspected" there is carbon on the intake valves. So I'm wondering if it was a mis-diagnoses only because of the engine rattle which occur on a cold startup which I'm looking now could be the timing chain tensioner. I know this is that wrong place to discuss this but has anyone encountered the timing chain tensioner going bad and it throwing the check engine light? They charged me a diagnoses fee so if they misdiagnosed it Ima have to ask for that refund
 

GertieGTI

Ready to race!
Is it not easy for shops to put a bore scope inside the intake manifold to verify the amount of carbon build up? This would be a much more fool proof method than throwing spark plugs, changing gas stations, ect.
 

FriggenT1

Banned
So I was driving just now and the check engine light is off I noticed. I know the Italian tune might just be placebo but I did that for about 20 mins yesterday and idk if that helped or not but the light is off. But then, I'm looking at the work order they quoted me and I see that the tech "suspected" there is carbon on the intake valves. So I'm wondering if it was a mis-diagnoses only because of the engine rattle which occur on a cold startup which I'm looking now could be the timing chain tensioner. I know this is that wrong place to discuss this but has anyone encountered the timing chain tensioner going bad and it throwing the check engine light? They charged me a diagnoses fee so if they misdiagnosed it Ima have to ask for that refund

The "Italian tune up" is really an old school method to blow everything out, get the injectors at max pressure, etc, etc, and you will feel a bit of a difference, but it will 100% NOT do much for the carbon that already exists. Run the car at over 3k for 20 to 30 minutes of preferably highway miles. It heats up the carbon, and you might get a LITTLE reduction, but again, nothing will get rid of it like manually cleaning it. These are direct injection engines, so unfortunately, no gas really touches the valves to clean them off. This is a problem that will continue and not much can be done.
 

FriggenT1

Banned
Yeah I never fully trust what dealership service agents tell me. I had mine recommended for the induction cleaning and fuel injector cleaning but at $400 and almost 30k miles and rather wait and use that money towards a manual cleaning lol. Dealerships can rob you of your hard earned cash and offer really no benefit.


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I went to a local shop that charged me like 110.00, I didn't need the gas tank additive, so it was the induction only...im not sure how much good it did as I was at 15 or 20k I think at the time.
 

InsuranceGuy

New member
My 2013 MK6 threw a CEL, dealer advised new intake manifold was needed. While this is covered under the powertrain warranty, he advised the carbon buildup was pretty bad and needed cleaning. Since manifold was already going to be off, the charge is $410. Would have been double had it not been off. I pulled the trigger based on the feedback here, so thanks to all posters and the OP.

FYI - I'm at about 56k miles now.
 

Chabnar

Passed Driver's Ed
I went to a local shop that charged me like 110.00, I didn't need the gas tank additive, so it was the induction only...im not sure how much good it did as I was at 15 or 20k I think at the time.

where did you go that only charged $110?
 

Steve Lai

New member
Hey guys. Good to reach and read this thread. Would like to share some experience with u.
I got a water pump leakage last month in my '12 GTI DSG at 45K KM. My mechanic charged US $250 for labour. I asked for concurrent carbon clean up since the IM would be lifted up, but he refused and advised me to pour several cans of eng clearner instead.
I decided to DIY & hv the pump replaced, a full clean up of carbon built up in valves as well as a thorough injectors cleaning.
The carbon deposit is awful coz we seldom hv chance to pull the car over 3500 rpm in Hong Kong. I'm gratifying that mechanic refused the carbon cleaning job which has triggered me to try out the DIY - such a rewarding experience indeed, though it took me weeks of research and 2 days of engine bay battle but definitely worth it.
 

GTIKage

New member
If this is not the correct place, let me know; but I am going to start this from the "Other End", as it were.

I have a 2010 [Stock] GTI w/133,000 miles on it. (Bought used this past May) Drive it combo city/highway about 35 min each way to work & back. No obvious symptoms of carbon buildup issues yet. Car runs great. Almost can't tell it's running when at idle. Accelerates smoothly.

I have been noticing quite a bit of carbon buildup on the tailpipes. Comes off on your finger, so it's fresh. Does this indicate anything related to the original topic of this thread? I run 93 octane. Run Top Tier every 4th fill up, and try to do a carbon cleaning run every month or so. No oil burning at all. Looks clean, too. The tailpipe thing is puzzling. It's not a diesel...

I am told this is "normal" for a GTI. Is it really? (Price we pay for DI & the quality of the "gas" we buy?)

Could it be style of driving? I have noticed more of a tailpipe build-up since I started letting the DSG do all the heavy work of shifting, instead of using manual-mode. My overall mileage is up; but am I sabotaging myself for carbon buildup at the intake valves, and the tailpipe buildup is just an indication of that?

Or may this be related to the chain tensioner failure I had 3500 miles ago, and the bad chain cover seal that puked oil for quite a while before I caught it? Could that cause a carbon buildup at the tailpipes? I lost some 2 quarts of oil in ~800 miles before I caught the leak, but almost nothing ended up on the ground. (Not sure where it went, unless on the windscreen of the poor guy driving behind me?)

Anyway - I'm wondering what kind of an issue it might (or might not) be.

Thanks!
 

hbrown0509

Go Kart Champion
If this is not the correct place, let me know; but I am going to start this from the "Other End", as it were.

I have a 2010 [Stock] GTI w/133,000 miles on it. (Bought used this past May) Drive it combo city/highway about 35 min each way to work & back. No obvious symptoms of carbon buildup issues yet. Car runs great. Almost can't tell it's running when at idle. Accelerates smoothly.

I have been noticing quite a bit of carbon buildup on the tailpipes. Comes off on your finger, so it's fresh. Does this indicate anything related to the original topic of this thread? I run 93 octane. Run Top Tier every 4th fill up, and try to do a carbon cleaning run every month or so. No oil burning at all. Looks clean, too. The tailpipe thing is puzzling. It's not a diesel...

I am told this is "normal" for a GTI. Is it really? (Price we pay for DI & the quality of the "gas" we buy?)

Could it be style of driving? I have noticed more of a tailpipe build-up since I started letting the DSG do all the heavy work of shifting, instead of using manual-mode. My overall mileage is up; but am I sabotaging myself for carbon buildup at the intake valves, and the tailpipe buildup is just an indication of that?

Or may this be related to the chain tensioner failure I had 3500 miles ago, and the bad chain cover seal that puked oil for quite a while before I caught it? Could that cause a carbon buildup at the tailpipes? I lost some 2 quarts of oil in ~800 miles before I caught the leak, but almost nothing ended up on the ground. (Not sure where it went, unless on the windscreen of the poor guy driving behind me?)

Anyway - I'm wondering what kind of an issue it might (or might not) be.

Thanks!


The carbon build up is normal with DI engines. Hopefully at that mileage you already had at least one carbon cleaning. From what it seems that driving manual mode or “drive” mode carbon build up is inevitable. Catch cans and meth injection help slow it down.



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jkdiver

New member
Danka

Thanks for the simple explanation, my hungry noob brain is grateful.
 

fredf

Go Kart Champion
The carbon build up is normal with DI engines. Hopefully at that mileage you already had at least one carbon cleaning. From what it seems that driving manual mode or “drive” mode carbon build up is inevitable. Catch cans and meth injection help slow it down.



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"Catch cans and meth injection help slow it down. "

There is no proof of this.
 
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