# Carbon cleaning opinions...



## nathanfaloon (Jun 3, 2016)

Anyone had any carbon cleaning done on these 2.0 tdis? Any noticeable benefits?

Had my a4 done once with over 100k but didn't notice much of a difference my tt only has around 60000 so not sure if I would even benefit?

Mostly just I find my tt is very loud (engine noise) at idle and was trying to think of ways to reduce it... Unless all 2.0 audi diesels are quite loud? Opinions apreciated 8)


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## GaryG (Aug 21, 2016)

If you're thinking of the professional version where some guy comes round and disconnects your fuel line, then theoretically is should remove *some *of the carbon. A mixture of diesel and Ammonia (or some caustic stuff like oven-cleaner) is run through the engine - the commonest version seems to be "Terra Clean".

There are no thorough, i.e. pictures in the cylinders before and after, reviews that I can find. Indeed, the reviews are either by the franchisees of "Terra Clean" or by people, very much like your comment, who drive the car afterwards and say "Well... I don't know if it is my imagination, but it seems to be pulling better."

The other recommendation is that as caustic liquids are very good at breaking down oil, only have the cleaning done immediately before changing the oil.

That said, for about £100 you can have it done and (if you change the oil afterwards) no harm has been done. I used to use Redex injector cleaner in a Volvo S80D that I had - Again, it seemed to do something good...


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## nathanfaloon (Jun 3, 2016)

The 'proffessional' version I've had done before was by engine carbon clean UK and they basically pumped hydrogen from just after my MAF and let the car idle on the hydro for about 10 mins then held the car at different rev ranges etc etc but I don't know what injection type the 2.0 tdis have so don't know if this would even be effective?

I remember my a4 was direct injection so that explains why it made very little difference...


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## GaryG (Aug 21, 2016)

nathanfaloon said:


> The 'proffessional' version I've had done before was by engine carbon clean UK and they basically pumped hydrogen from just after my MAF


This is basically combining hydrogen with the oxygen from the air to create water/steam. Without much evidence, the water is supposed to loosen the carbon that is then ejected through the exhaust.

There are a few youtube videos on decarbonising with water (which is the same thing as adding hydrogen but a lot cheaper) - the basis of the belief that the system works is that it is compared to pressure washing. However, a moment's thought will result in the realisation that it is nothing like pressure washing.


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## SwissJetPilot (Apr 27, 2014)

I think walnut blasting is really the only way to go for the intakes especially with a Direct Injection engine.


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## TT-driver (Sep 14, 2010)

Hydrogen and oxygen combined aren't going to do much without a spark. So putting that into the inlet won't fix anything when it comes to cleaning off carbon deposits around the intake valves. The spark/combustion is in the cylinder itself. All TT's are equipped with a system that helps cleaning carbon deposits in the cylinders. It's the pedal on the right, just push it to the carpet more often.

Carbon deposits mainly sit in the air intake manifold and around the intake valve stems. With direct fuel injection, fuel doesn't reach that area. That's why carbon can build up. Chemicals may break loose some of the deposits and flush it into the cylinders. However I'm not sure if that is the right way forward. The catalytic converter or particle filter won't cheer when receiving that cocktail of carbon and chemical dissolvents. And if that mixture ends up around the piston rings, increased oil consumption may occur. So if cleaning is really required, I'd take the intake manifold off and clean mechanically.

Making the engine work harder for a longer period of time may glow some of the carbon off from the intake valves too.


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## nathanfaloon (Jun 3, 2016)

general consensus seems to be its a waste of time then? 

anyone have any ideas what to look for as to why my 2010 tt sounds like a tractor? thought the carbon might have been making the engine work harder etc etc cause ive heard reports of vw caddys etc becoming infinitely quieter after a clean so thought the same might apply here.

i drive it fairly hard nearly every day so thats not an issue thankfully lol :roll:


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## koskotas (Dec 1, 2008)

In direct injection engines the its very difficult to clean inlet valves through chemicals ! Also its impossible to clean them by adding chemicals to fuel as the injector sprays direct in the chamber ( direct injection ). I am studding a bit now as i wanted to clean the valves on my car and the only method that i saw and looks to work its with walnut shell blasting. this method is very common on BMW/mini/ Peugeot engines. BMW also have special tool to do this !

BEFORE :









AFTER :


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## SwissJetPilot (Apr 27, 2014)

Another option rather than wall nut shells would be dry ice blasting. One advantage of dry ice is the lack of mess and debris left behind. My concern with wall nut shell blasting would be FOD (Foreign Object Debris). As indicated in the picture, these tiny particles of wall nut shell pose a problem if not completely removed. Imagine trying to ensure the seal of a gasket if this material is not completely removed. Then consider whether or not they are up in the valve stem and valve guide. It's a solution to be sure, but in an engine that's not disassembled, it may not be the best solution.

Dry-ice blasting - Wikipedia

Here are a few links to companies in the UK that offer this sort of service. I have no personal experience with this technique on my vehicle, but it's an option to consider. As with any service, the quality and thoroughness is always dependent upon the skills of the individual doing the work.

http://dryiceuk.com/blast-cleaning/blast-cleaning-faq/

http://dev.miracledetail.co.uk/services ... detailing/

Domain parking page


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## koskotas (Dec 1, 2008)

SwissJetPilot said:


> Another option rather than wall nut shells would be dry ice blasting. One advantage of dry ice is the lack of mess and debris left behind. My concern with wall nut shell blasting would be FOD (Foreign Object Debris). As indicated in the picture, these tiny particles of wall nut shell pose a problem if not completely removed. Imagine trying to ensure the seal of a gasket if this material is not completely removed. Then consider whether or not they are up in the valve stem and valve guide. It's a solution to be sure, but in an engine that's not disassembled, it may not be the best solution.
> 
> https://en.wikipedia.org/wiki/Dry-ice_blasting
> 
> ...


The reason that wallnut is used is that the fools can easy burn up with no additional problems ! Atrer the work done with some good cleaning ( compresses air ) you can remove all un-nessesary debris


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## SwissJetPilot (Apr 27, 2014)

@ *Koskotas* - I agree that wall nut shells are a very good media for this type of work. However the debris left behind is a major concern with regards to sealing and contact surfaces in a closed engine condition. This is exactly why dry-ice is used on commercial turbine engines on compressor blades, where FOD is a major concern, since CO2 leaves no residue. In this picture, the valves are closed so the risk of FOD isn't that bad. However, the last thing you need is doing this when they're open, resulting in a cylinder full of wall nut shells! In this case, CO2 makes more sense.

IMHO the four critical surfaces for removing carbon deposits up would be (1) valve seats, (2) injectors, (3) glow plugs and (4) piston head. The piston is really not that critical since only the surface of the piston head would be affected and the change in cylinder volume would be almost inconsequential (unless it's a serious case of neglect).

However carbon buildup between the valve seat and valve seat face interface could effectively result in reduced cylinder pressure if carbon deposits prevent proper valve closure; e.g leaks resulting in reduced cylinder pressure.

While it may be possible to CO2 blast the valve seats in a close engine, how well this can be done would be my concern given limited access to the valve seats themselves as one would have to be able to rotate the cam in order to open all the valves in each cylinder in order to effectively clean each valve seat. Not an easy thing to do!

For this reason, in a closed engine condition, the chemical solution would probably be the best option on a regular basis to prevent build up ever becoming significant. However, as mentioned above if the build up is significant, the particles released downstream into the cat could be problematic. If the carbon build up is so severe that it affects proper valve seating, it might be worth a head removal and address issue of de-carbonizing in an open engine condition.

Since both the injectors and glow plugs can be easily removed, they would lend themselves to wall nut shell blasting and would probably have the most immediate impact on performance given their role in the combustion cycle with respect to fuel flow and ignition. Build up of carbon in the injectors would have obvious consequences with respect to flow, volume and dispersion as the fuel is introduced to the cylinder. Carbon build up around the glow plug could effectively reduce the operating temperature since it would act as an insulator.

So...I'd start with the two easy points of maintenance first; glow plugs and injectors. Then consider the valve seats if build up is significant. Chemical applications or CO2 are an option in a closed engine condition, with wall nut shells limited only to an open engine condition. And some sort of fuel system solvent/cleaner as regular maintenance to help minimize build-up.

Just my two cents worth.


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## pazaz29 (Oct 10, 2016)

Im going to give Terraclean a go soon on my MK2 TTS and see if it feels better etc.

I have previously used revive turbo cleaner on a BMW 123D and it made it purr like a kitten after. This was on a diesel so I have no idea what use it will be on a petrol turbo. The revive is easy to do as well.


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## Malc27 (Sep 28, 2016)

pazaz29 said:


> Im going to give Terraclean a go soon on my MK2 TTS and see if it feels better etc.


I would be interested to know the outcome of this.


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## TT-driver (Sep 14, 2010)

I don't think the valve seats are going to cause a problem. The valves rotate while in operation and the constant hammering of the valves on the seats will keep the contact surfaces pretty clean. So IMHO no reason for loosing compression on that. There is another reason for loosing compression: due to carbon build up, the amount of air that can be sucked into the combustion chamber may become less due to inlet area restriction.

The intake manifold may clog up if there is an EGR active (I'm not sure what VAG software is doing these days...). The combination of EGR gasses and oil vapours gives a nice and sticky mass.

Injector cleaner or fuels with additional cleaning agents like BP Ultimate will help cleaning the injectors. Frequent oil changes will keep piston rings clean(er). The intake area: often elbow grease is best. Your hands will become dirty and will stay so for at least a week. That's my experience when cleaning the intake of a Honda diesel engine a couple of years ago. In the end all work made no difference


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## Stealth69 (Jun 25, 2012)

Just don't drive it like a pussy and enjoy it for what it was made for and you'll not get a great deal of carbon build up lol


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## andez1781 (May 27, 2015)

I removed the intake manifold and cleaned the valves with good old elbow grease and carb cleaner (rotating the engine as required), and mines is a petrol and my it was gummed up pretty well. The joys of direct injection . As said before, no cleaners will reach the back of the valves .


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## SwissJetPilot (Apr 27, 2014)

@ *Stealth* - To your point...

"Just don't drive it like a pussy and enjoy it for what it was made for and you'll not get a great deal of carbon build up lol"

Since you guys in the UK can't run over 70-mph then...well...nuf said! ;-) I'd recommend you bring your TT's over to Germany once a year just to blow the carbon out - give it the old "Italian Tune-up".

Fortunately I head north at least once a month, so a nice long 4-hour cruise at 125-mph is probably doing wonders despite the 3.2 VR6 being indirect and not as susceptible to this problem.


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## Stealth69 (Jun 25, 2012)

SwissJetPilot said:


> @ Stealth - To your point...
> 
> "Just don't drive it like a pussy and enjoy it for what it was made for and you'll not get a great deal of carbon build up lol"
> 
> ...


Didn't say in 6th gear  I'm sure everyone in the UK has a favourite bot of "private" road where by they can stretch the TT's legs :lol:

But I like your thinking, group outing to Germany anyone?


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## Anakin (Apr 19, 2011)

Terra clean etc is a waster of time, I had the intake valves cleaned at awesome gti, maifold off and manual clean of the deposits. before and after RR setions.

386.57 bhp @ 6480 rpm before to 414.60 bhp @ 5810 rpm after , this was on a TTRS with 45k miles on it.


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## GaryG (Aug 21, 2016)

Anakin said:


> Terra clean etc is a waste of time, I had the intake valves cleaned at awesome gti, maifold off and manual clean of the deposits. before and after RR setions.


Out of idle curiosity, how much did that cost?


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## Anakin (Apr 19, 2011)

GaryG said:


> Anakin said:
> 
> 
> > Terra clean etc is a waste of time, I had the intake valves cleaned at awesome gti, maifold off and manual clean of the deposits. before and after RR setions.
> ...


you'd be best of rinning awesome , I had full service done and the rolling road setions too that was around £500 all in. Think I had spark plugs and Race oil put in too ...


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## andez1781 (May 27, 2015)

Anakin said:


> Terra clean etc is a waster of time, I had the intake valves cleaned at awesome gti, maifold off and manual clean of the deposits. before and after RR setions.
> 
> 386.57 bhp @ 6480 rpm before to 414.60 bhp @ 5810 rpm after , this was on a TTRS with 45k miles on it.


 that's what my valves looked like aswell ,but I didn't get them as clean as awsome did though .but mind you if was a lot cheaper  , didn't have a rolling road , but the butt dyno did feel a difference .


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## GaryG (Aug 21, 2016)

Anakin said:


> you'd be best of ringing Awesome , I had full service done and the rolling road sessions too that was around £500 all in. Think I had spark plugs and Race oil put in too ...


Thanks. I've bookmarked the page. Ill ring them when the time comes for a service.


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## Rouju (Mar 6, 2011)

Anyone know how much a carbon clean costs and what I should ask for?

Audi said my was throwing up a fault code due to carbon in the cylinder?

Is there a way I can check (for dummies)

I wouldn't say it feels down on power though or is it that marginal you wouldn't


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## GaryG (Aug 21, 2016)

Rouju said:


> Anyone know how much a carbon clean costs


See Anakin's reply above:


Anakin said:


> I had full service done and the rolling road sessions too that was around £500 all in. Think I had spark plugs and Race oil put in too ...


So the answer seems to be £200 - £300. But that's at an indie.


> and what I should ask for?


"I would like you to clean the inlets and valves of carbon."


> Is there a way I can check (for dummies)


No. You have to assume that after about 40.000 miles that there'll be carbon deposits.


> is it that marginal you wouldn't


Anakin's graph shows about 7% down on max hp before the clean and the problem is that it is not sudden - it is very gradual and you don't notice it.


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## pazaz29 (Oct 10, 2016)

I did a revive turbo clean on my TTS last week and loads of black sooty crap came out of my exhausts. Driving lovley now.

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## Roller Skate (May 18, 2015)

Next week I'm having the inside of my tyres cleaned ... apparently it makes the tyres more "grippy".


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## Barr_end (Oct 19, 2016)

Roller Skate said:


> Next week I'm having the inside of my tyres cleaned ... apparently it makes the tyres more "grippy".


This is the best reply in this thread :lol:

As has been said by a few in this thread, any terrawank etc cleaning service will not remove the carbon build up in the inlet manifold. The only way is by actually removing it. Either via a watnut blasting or by manual removing with pick/bushes with carb cleaner.
Also I couldn't imagine what the chemicals used pumped through the fuel system does to the injector baskets, if you take a look at the injector clinic the damage to the filter baskets from 'just fuel' over time are ruined! Broken down to even completely missing.


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## FJ1000 (Nov 21, 2015)

The Hydrogen carbon cleans are a con.

I tested this with 3 cars and there is a long thread on RS246 and a YouTube vid on it (search "putting EngineCarbonClean to the test" - and read the comments.)

I did before and after runs at a dyno. I then took the B7 RS4 to MRC tuning who removed the inlet manifold and inspected the results of the "clean".

The manifold and valves were covered in carbon, some of which had turned to sludge and clogged a hose (which I had replaced). After a proper manual clean - the car gained 44PS.

The VW Golf GTi I also had cleaned gained no power at all, and a borescope showed same levels of carbon as before the clean

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