Carbon Cleaning (DIY or let the pro do it?)

[J0rgii]

Hey guys I am fairly new to the forums and I just wanted to start off by saying this site is awesome when it comes to providing information especially for guys like me that are still learning how to maintain their Audis. Forgive me if this thread has already been posted somewhere like I said I'm still fairly new. I wanted to start a convo on carbon cleaning and I know there is a bunch of Audi owners here who can pass along on some great applicable/hands on knowledge.

So I purchased an A4 at 90k miles and after some research I found out these cars are prone to carbon buildup inside of the intake valves and fuel injectors. I peeped some really good vids on how to clean it up on your own with some wire brushes, brake cleaner, picks, etc. But the vehicles I saw were of cars that had way less mileage than my car. Like I think one was a Golf R at like 10k miles and it looked pretty bad lol. Granted I need to go ahead and remove my intake manifold and just inspect it myself but I am going to assume that the valves on this A4 sitting at 90k is going to be horrendous. I have 2 options either do it myself and clean it up as best I can or take it to a special Audi mechanic I know. My guy is charging a tough $450 though and I think he's slightly overcharging. Anybody with hands on experience feel free to debate/defend that $450 charge I understand how laborious it can be working on these vehicles. So what do the Audi gods here have to say? Should I just use some at home tools to clean it up or take it to the mechanic where he is going to use his special tools (i.e air brush kit) that a regular being like myself doesn't have?

[A4x]

I think $450 is a fair price considering the labor involved, with one stipulation: have your mechanic provide you with before and after pictures of all 4 sets of valves. I say this because some guys might cut corners and you won't get the full benefits if the valves are not fully cleaned. What did he suggest you do about re-sealing the injectors? There will be some parts costs here for the seals.

Personally, I bought the required tools and walnut shell blasted mine. I had a fun time doing it, and it's really not that hard. I wouldn't attempt this without walnut shell blasting; picking and scraping at the valves is not my idea of fun.

If you already have an air compressor and a shop vac, all you need is a Harbor Freight media blaster and a box of walnut shells. That will run you about $50. Then you need the adapter from Ford Perfect or try to rig up your own system so as not to make a mess of your engine bay.

Don't forget that you should get new seals for your injectors. I chose to purchase all new injectors since they come with fresh seals, and from RockAuto at that time they were only about $50 each.

Read through these 2 threads for some more info:
https://www.audizine.com/forum/showt...arbon+cleaning

https://www.audizine.com/forum/showt...arbon+cleaning

[Ford Prefect]

Thanks @A4x for posting my thread. I think this should be a great first DIY on the 2.0T. I do recommend walnut shells for ease, quickness, and to save your back. Even if you’re young you’ll thank me when your 46.

Good way to get to know your motor a little better. I had my B8 S4 for a month and ripped the SC and intake manifolds off for this.

Alldatadiy is a relatively cheap subscription service if you’d like more guidance. I have it for all of my cars.


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[NoiseBoy]

Welcome to the world of Audi, and the forum!

Intake valve carbon cleaning isn't a hard diy, just time consuming.

The Harbor Freight walnut shell blaster is a tool to consider, and I did purchase one when I cleaned my valves. Since we are in quarantine and I was not in a rush to get the car back on the road, I experimented with 4 different ways to clean the valves:

1. Walnut shells.
2. Soaking with gasoline.
3. Soaking with Berryman B-12 Chemtool
4. Soaking with elbow grease. (haha)

Elbow grease worked, but took a long time. I used a Harbor Freight brush kit with nylon/plastic bristles. There were 6ish brushes with small/med/large sizes for $5. I cut off the hoop on the handle end, and the metal tip off of the brush end and used a power drill to speed up the process. The large sizes were great for the valves/intake ports, and the small ones were great for the injector ports. I used a pick to grab the loosened carbon deposits, and deposit them onto a rag. Took about an hour, but the valves and intake ports got clean.

The walnut shells seemed to work ok, but the Harbor Freight media blaster nozzle kind of blows (HA!) for this. It's not a detailed nozzle... shotgun with birdshot vs. sniper rifle if that makes sense... It got some areas of the valves/intake clean really fast, but I couldn't aim it at some places. Back of the intake stems for example. I'm also a bit worried about damaging the valve seals.

Soaking with gasoline for an hour or so helped soften the carbon a bit. I used the same brushes/drill and it cleaned up nicely.

Soaking with Berryman B-12 for an hour... This was amazing! Using paper towels to soak up the chemical out of the intake, the paper towels were BLACK, and brought globs of carbon with it. After I got the liquid out of the intake, I went after the valves with the brushes/drill. After that I went in there with some shop rags and a finger. The carbon basically wiped off. I went back and used this on the other 3 cylinders to make sure I got everything. MAKE SURE TO USE GLOVES!!! I mean gloves... Thick, past the wrist, doing dishes kind of homemaker gloves. The black mechanic gloves I use didn't stand up, the B-12 ate through the finger tips. I noticed quickly, and no damage to my skin, but better safe than sorry.

You said you looked at a DIY, so I'm not going to bore you with instructions/tools you already know about. I would follow what A4x suggested and replace injectors while you're in there. I had one fail open 3 months ago, and I only replaced the failed injector because funds were tight. Fast forward 2 months, and I had another injector fail open. This time I replaced all 4 injectors, seals, carbon cleaned, and replaced the intake manifold.

I'd suggest replacing the manifold while you have it off. It's a known failure part. The Audi version is $550 from your vendor of choice, but the VW version is $150. It bolts right up. The only difference is a tab above the throttle body which I think is for a wire holder clip on transverse engines. On our longitudinal engines, it touches the underside of the plastic engine cover, but doesn't effect it fitting right.

The only other thing I'm going to suggest, is to take your time. Make sure you take it easy putting bolts back into the cylinder head: aluminum is soft and you don't want to strip the threads.

Good luck!

[Spawne32]

lol Berryman B-12 is so corrosive it isnt even funny. I buy it in gallon containers to clean engine parts when rebuilding engines. You can dip a piston and rod assembly in there overnight, and the next morning it comes out so clean you could resell them as new. Problem with soaking the valves with the Berryman is that if your valves don't seal very well, you will be cleaning the cylinder and the crankcase as well. Ask me how I know.

[NoiseBoy]

Pretty sure I DONT want to ask you how you know, haha!

I decided to give the B-12 a shot because I've heard people using it to do the same as you. I did make sure the valves were closed all the way: I let some gas sit in there for 10 min, and made sure the level stayed the same / not leaking into cylinder. I wasn't brave enough to let the B-12 soak for more than an hour, and honestly it wouldn't need to.

[Spawne32]

Pretty sure I DONT want to ask you how you know, haha!

I decided to give the B-12 a shot because I've heard people using it to do the same as you. I did make sure the valves were closed all the way: I let some gas sit in there for 10 min, and made sure the level stayed the same / not leaking into cylinder. I wasn't brave enough to let the B-12 soak for more than an hour, and honestly it wouldn't need to.

Oh it works, good too. Really depends on how bad the valves were prior, I mean I probably spent several hours scrubbing, soaking and back and forth and still never got them as clean as I could with walnut blasting. Next time around I plan to buy the 034 motorsports adapter and walnut blast, saves time and money.

[J0rgii]

Welcome to the world of Audi, and the forum!

Intake valve carbon cleaning isn't a hard diy, just time consuming.

The Harbor Freight walnut shell blaster is a tool to consider, and I did purchase one when I cleaned my valves. Since we are in quarantine and I was not in a rush to get the car back on the road, I experimented with 4 different ways to clean the valves:

1. Walnut shells.
2. Soaking with gasoline.
3. Soaking with Berryman B-12 Chemtool
4. Soaking with elbow grease. (haha)

Elbow grease worked, but took a long time. I used a Harbor Freight brush kit with nylon/plastic bristles. There were 6ish brushes with small/med/large sizes for $5. I cut off the hoop on the handle end, and the metal tip off of the brush end and used a power drill to speed up the process. The large sizes were great for the valves/intake ports, and the small ones were great for the injector ports. I used a pick to grab the loosened carbon deposits, and deposit them onto a rag. Took about an hour, but the valves and intake ports got clean.

The walnut shells seemed to work ok, but the Harbor Freight media blaster nozzle kind of blows (HA!) for this. It's not a detailed nozzle... shotgun with birdshot vs. sniper rifle if that makes sense... It got some areas of the valves/intake clean really fast, but I couldn't aim it at some places. Back of the intake stems for example. I'm also a bit worried about damaging the valve seals.

Soaking with gasoline for an hour or so helped soften the carbon a bit. I used the same brushes/drill and it cleaned up nicely.

Soaking with Berryman B-12 for an hour... This was amazing! Using paper towels to soak up the chemical out of the intake, the paper towels were BLACK, and brought globs of carbon with it. After I got the liquid out of the intake, I went after the valves with the brushes/drill. After that I went in there with some shop rags and a finger. The carbon basically wiped off. I went back and used this on the other 3 cylinders to make sure I got everything. MAKE SURE TO USE GLOVES!!! I mean gloves... Thick, past the wrist, doing dishes kind of homemaker gloves. The black mechanic gloves I use didn't stand up, the B-12 ate through the finger tips. I noticed quickly, and no damage to my skin, but better safe than sorry.

You said you looked at a DIY, so I'm not going to bore you with instructions/tools you already know about. I would follow what A4x suggested and replace injectors while you're in there. I had one fail open 3 months ago, and I only replaced the failed injector because funds were tight. Fast forward 2 months, and I had another injector fail open. This time I replaced all 4 injectors, seals, carbon cleaned, and replaced the intake manifold.

I'd suggest replacing the manifold while you have it off. It's a known failure part. The Audi version is $550 from your vendor of choice, but the VW version is $150. It bolts right up. The only difference is a tab above the throttle body which I think is for a wire holder clip on transverse engines. On our longitudinal engines, it touches the underside of the plastic engine cover, but doesn't effect it fitting right.

The only other thing I'm going to suggest, is to take your time. Make sure you take it easy putting bolts back into the cylinder head: aluminum is soft and you don't want to strip the threads.

Good luck!

Ok I see that Berryman B-12 Chemtool is available in any auto parts store it's also pretty cheap I am going to most likely take this approach with it. I actually purchased that harbor freight tool myself & good advice for the injectors. After I take a look at them I might just consider replacing them altogether.

[J0rgii]

lol Berryman B-12 is so corrosive it isnt even funny. I buy it in gallon containers to clean engine parts when rebuilding engines. You can dip a piston and rod assembly in there overnight, and the next morning it comes out so clean you could resell them as new. Problem with soaking the valves with the Berryman is that if your valves don't seal very well, you will be cleaning the cylinder and the crankcase as well. Ask me how I know.

You brought up a great point that I'm sure is probably in one of those threads A4x posted. How the heck do you close the valves on the B8 2.0t? I've seen some good vids on the carbon cleaning that emphasis making sure they're close but don't really show how to close the valves lol.

[NoiseBoy]

You need to manually turn over the crankshaft. 24mm 12 point socket (I think...). It has to be a fairly shallow breaker bar or ratchet, there’s not a lot of room between the crankshaft and radiator. ALWAYS TURN CLOCKWISE! Once you have the manifold off you’ll be able to see what’s going on.

You should also check for your cylinders to be TDC. I used a short (16”) piece of solid copper wire, put that in the spark plug port, and turned the crank until the wire stopped moving up.

If cylinder 1 is TDC, you can clean valves on cylinders 1, 2, 3 at the same time. You would have to turn the crank to close the valves on cylinder 4. Put some gas in the intake ports and let it sit to make sure the valves are sealed before you start dumping B12 in there.

B12 is cheap enough, grab 4 cans of it. There’s no way you should need that much of it, but it’s better to have it.

[A4x]

You need to manually turn over the crankshaft. 24mm 12 point socket (I think...). It has to be a fairly shallow breaker bar or ratchet, there’s not a lot of room between the crankshaft and radiator. ALWAYS TURN CLOCKWISE! Once you have the manifold off you’ll be able to see what’s going on.

This is what I did. It's easy.

Make sure to get the shallowest socket possible and don't use any adapters (like quarter inch to eight inch) as they add length.

[S-Liner]

I think $450 is fair.

IF you don’t own an air compressor capable of sustaining continuous sufficient PSI while you have the walnuts blowing through a media blaster.

However, IF you own a good air compressor, blaster, and have the media....by all means do it yourself. Shit is easy but a pain in the ass to get the remaining cylinder to TDC. I ended up turning my engine over after removing the fuel pump fuse.

If you do this on your own, be careful and don’t strip out your intake manifold threads like I did. DO NOT German torque those nuts in place, more than likely you’ll strip them fawqurs out.


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[Spawne32]

You brought up a great point that I'm sure is probably in one of those threads A4x posted. How the heck do you close the valves on the B8 2.0t? I've seen some good vids on the carbon cleaning that emphasis making sure they're close but don't really show how to close the valves lol.

Well the problem more so is that if your valve seats are worn, which I think mine probably are, it will just run right out over a period of time. But yes, manually turning the crankshaft is about the only way to rotate it. You can pull all the spark plugs to make it easy, and a really long screwdriver will tell you when #1 is at TDC.

[Zuzuwu]

Very easy job if you have any type of mechanical know how. Intake takes all of 10 minutes to pull. I used a spray cleaner and a pick to pre-clean, blew it out with compressed air, then walnut blasted with a cheap little blaster from harbor freight. Very easy job. Made absolutely no difference in performance or mpg, a complete waste of time. Very little buildup on the valves to begin with.

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[Spawne32]

Very easy job if you have any type of mechanical know how. Intake takes all of 10 minutes to pull. I used a spray cleaner and a pick to pre-clean, blew it out with compressed air, then walnut blasted with a cheap little blaster from harbor freight. Very easy job. Made absolutely no difference in performance or mpg, a complete waste of time. Very little buildup on the valves to begin with.

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It depends on how old your car is, B8's have some of the worst carbon buildup i have ever seen, especially if they go 100k miles with no intake cleaning.

This is just one of my ports the first time I did it.

[mtroxel]

Made absolutely no difference in performance or mpg, a complete waste of time. Very little buildup on the valves to begin with.

Same here. Did mine at 119,000 miles. This is cyl 4 before. I let them soak in Gumout for an hour (valves seal very well). I got them very clean, it made 0 difference.

[J0rgii]

Same here. Did mine at 119,000 miles. This is cyl 4 before. I let them soak in Gumout for an hour (valves seal very well). I got them very clean, it made 0 difference.

Whoa great image, I think you just showed me what my cylds are going to look like when I start this job lol

[Spawne32]

Same here. Did mine at 119,000 miles. This is cyl 4 before. I let them soak in Gumout for an hour (valves seal very well). I got them very clean, it made 0 difference.

I think its a little bit too broad to say it makes zero difference. It really depends on the amount of carbon that is built up on the valves. Obviously some are bad enough (including other cars) that the build up dramatically effects the way the engine runs. The intake ports are obviously designed in a specific way that is optimal for airflow into the engine, once the carbon starts changing that flow, it changes the way the engine runs. Whether that can be felt is debatable. Some of our cars develop a poor idle quality when they get this bad, others dont. Mine had some spots where it was a 1/8th of an inch thick in carbon, that shrinks the size of the intake port obviously.

[mtroxel]

I think its a little bit too broad to say it makes zero difference.

I'm sure you're right, and I wasn't saying its worthless for everyone. But I also see guys talking about how this is a chronic issue in every TSI motor. It really wasn't in mine. Maybe I've just had a healthier PCV system than some, or maybe its the Italian tune ups I give it every morning when I pull on to the freeway to my office. I'm going with the Italian tune-up.

[S-Liner]

In my case, the idle was slightly improved and throttling through the power band seemed smoother to me. Could be the placebo effect who knows, but it felt improved to me.

I did mine at 130K and the crud on those valves was nasty AF. I’m a mechanic in the Air Force and work on diesel, gas, and turbine engines. I’ve seen some shit. Diesel and gas turbine are some of the worst when it comes to carbon build up. This TSI motor definitely ranks up there.


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[Theiceman]

I can tell you after 130k miles on mine I could not even see the valves it was do caked. But car ran flawless before and after so it made zero difference for me personally.

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[ps2cho]

I can tell you after 130k miles on mine I could not even see the valves it was do caked. But car ran flawless before and after so it made zero difference for me personally.

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As with most car maintenance, it’s being proactive and fixing issues before you notice them is the best way to handle it.

I’d love to see someone do a couple dyno runs before/after, that would clear up the books on its effect.

[Theiceman]

As with most car maintenance, it’s being proactive and fixing issues before you notice them is the best way to handle it.

I’d love to see someone do a couple dyno runs before/after, that would clear up the books on its effect.

I'm not sure you would see much there.
For me I would like to see if someone has cold start misfires and does a carbon clean and only a carbon clean of it fixed it.
Usually people do new Injector's or seals or some other thing while doing it so the route cause is difficult to tell

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[S-Liner]

Ahhh yes, forgot about the cold starts!

So prior to my carbon cleaning, my high idle made some dirty sounds and had an excessive amount of engine shake (bad mounts). Sounded like a Hoover on its last leg.

After the cleaning, the shake was almost gone and the high idle sound effects tapered off quite a bit.


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