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Carbon Buildup @ 80k - Before and After Photos

jcw122

Passed Driver's Ed
Location
PA
Carbon Buildup @ 80k - Before and After Photos (+3mo followup)

UPDATED 7/30/19: I can confirm that 3 months and 3k miles after this post, I have not had any misfires per my OBDeleven reader! I believe the cleaning fixed it 100%.

Hi all,

I'd like to present the visual results of my 2015 GTI's carbon cleaning at 80k miles. I bought my car in December at 76k miles. Based on all of my research of the MK7, I've never seen anyone report issues with carbon build-up. On top of that, I've seen a lot of people suggest that carbon isn't much of an issue on the MK7. I was able to obtain before and after photos that strongly suggest that isn't true, at least for my specific car. Believing it wasn't much of an issue, I was totally shocked when I saw the "before" photos. I hope this can serve as a useful data point for our community, as I'm assuming my car is further up there in mileage compared to average.

As some background, I purchased my GTI used at 76k, and noticed it had been running rough at idle, and I had the EPC light come on 5 times in 3 months, with misfire codes being thrown in the ECU. I replaced the spark plugs and coil packs myself, which helped idle but not EPC and misfires. EDIT: When I took it to the dealership, they asserted it was due to carbon buildup that they identified via a bore-scoping and the codes involved.
Here's my previous thread on the topic: https://www.golfmk7.com/forums/showthread.php?t=51592

Anyway, I ended up taking my car to a shop that did walnut blasting for $600 (+tax) in Philly. (EDIT: Woodlawn Garage, for those asking).

Below are the before and after photos. I was totally shocked to see how bad the build-up was. Unfortunately, the shop didn't take the best "before" photos, as they're out of focus, but I believe they do a good enough job of showing the severity of the carbon build up.

Before:





After:





Dividers:




Thanks,
 
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jcw122

Passed Driver's Ed
Location
PA
So... How does it run, after the cleaning?

Sent from my SM-G955U using Tapatalk

I've only been in heavy traffic with it so far, so I haven't had much of a chance to assess. My initial impressions were that it felt like it idled a bit smoother, but that was already mostly fixed with the spark plugs and coil packs.
 

Slow4

Passed Driver's Ed
Location
MN
Interesting. Either way, can't be worse than my old 335, had to have that carbon cleaned at 40K
 

swcrow

Autocross Champion
Location
Virginia
Car(s)
7.5
BRAVO OP.....bravo. Pics for the win. The debate will begin on what the driving style was like before your purchase and how different driving styles and tier gas would have contributed, but really glad you took pics for all of us who haven't experience this yet.

 

Klrider44

Go Kart Newbie
Location
Bucks county PA
I've only been in heavy traffic with it so far, so I haven't had much of a chance to assess. My initial impressions were that it felt like it idled a bit smoother, but that was already mostly fixed with the spark plugs and coil packs.

Yea I did a carbon clean on my B7 A4 at like 140K and it looked pretty similar to your valves and to be honest I didn’t notice any difference with how the car drove and performed. I only did it because I was taking the intake manifold off anyway. I’ll prolly only clean the valves on my MK7 if I go MPI, then I’ll never have to worry about it again.
 

Stija

Go Kart Newbie
Location
Az
Car(s)
BMW Saab Subaru VW
What was this walnut blasted? How much did it run you if you don't mind me asking/what shop?
Its in the OP, 600$.

It was dirty, now its clean. Just like a new pair of socks, you feel great about it for some time then life goes on. Is it needed? It depends on your definition of needed.

I don't think it is. In my opinion it is throwing away money especially if there are no symptoms one is trying to remedy thinking its the carbon buildup.
 
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swcrow

Autocross Champion
Location
Virginia
Car(s)
7.5
Its in the OP, 600$.

It was dirty, now its clean. Just like a new pair of socks, you feel great about it for some time then life goes on. Is it needed? It depends on your definition of needed.

I don't think it is. In my opinion it is throwing away money especially if there are no symptoms one is trying to remedy thinking its the carbon buildup.


Until it happens to you, I'm sure everyone will think this. Buddy at work had massive stumbling, misfires and CEL in his Mk6...plugs, packs...dealership threw everything at it. It wasn't until the walnut service when it all *magically* disappeared.
 

russiankid

Drag Race Newbie
Location
PA
Its in the OP, 600$.

It was dirty, now its clean. Just like a new pair of socks, you feel great about it for some time then life goes on. Is it needed? It depends on your definition of needed.

I don't think it is. In my opinion it is throwing away money especially if there are no symptoms one is trying to remedy thinking its the carbon buildup.

Missed that, thanks.
 

jcw122

Passed Driver's Ed
Location
PA
BRAVO OP.....bravo. Pics for the win. The debate will begin on what the driving style was like before your purchase and how different driving styles and tier gas would have contributed, but really glad you took pics for all of us who haven't experience this yet.

Thank you! I really do hope it gets the conversation started (or restarted) on MK7 carbon buildup.

To my knowledge, the prior two owners lived in rural/suburban Virginia, and based on the mileage and year, my guess is they were likely commuting a good distance.

Its in the OP, 600$.

It was dirty, now its clean. Just like a new pair of socks, you feel great about it for some time then life goes on. Is it needed? It depends on your definition of needed.

I don't think it is. In my opinion it is throwing away money especially if there are no symptoms one is trying to remedy thinking its the carbon buildup.

To provide further detail, a VW dealership in my area specifically identified the cause of the misfires to be due to the carbon build up. So in that sense, it was definitely needed for this car due to the symptoms.

What was this walnut blasted? How much did it run you if you don't mind me asking/what shop?

I ended up going with Woodlawn Garage in Philly (Germantown neighborhood).
 
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Stija

Go Kart Newbie
Location
Az
Car(s)
BMW Saab Subaru VW
I think I read that in another thread, if that was you. Still, I have my doubts that carbon buildup causes misfires. But I'm no VW dealer..
 
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