Carbon Clean / Valves / Turning motor - C6 S6

A6 All/ S6 All
#1

Hi All,

Took my intake manifold off today in order to do a carbon cleaning.

Definitely needs it - on top of this, the carbon has caused my manifold flaps to also fail.

Anyways, I have been watching some videos and reading up on the process, and I decided to try the method where you fill the intake runners with carbon cleaning solution and let it soak, then vac it out or soak it up with a sponge, which should allow you to then easily wipe away what’s left.

I bought a can of LiquiMoly Petrol Engine Intake Decarb
http://www.liqui-moly.com.au/products/petrol-engine-intake-decarb-2733/

Now, obviously before you can fill the intake runners, you must make sure the valves are completely shut, lest you fill up your cylinders and flood the engine - or worse, cause the engine to hydrolock (is that even possible with this type of fluid?)

Because the valves are so carboned up, it is hard to see/be 100% sure the valves are closed.

Is there a way to tell based on one cylinder’s valve position which other cylinders will be 100% closed?

Further, obviously at any angle of the engine, some valves will be open. How do you manually turn the engine over to operate the valves? Normally I would do this with the crank nut, but this car doesn’t have a crank nut!

Has anyone done this before?

Am I going about this the wrong way and making life difficult for myself?

Thanks for any help/replies!

Cheers,
P

#2

Well you are in good hands.

1 go get some starting fluid. Spray that into the cylinders that you believe are closed. Spray till you get a standing puddle of fluid. If the fluid sinks then the valve is still open. Spray until you find the valves that are closed. You should have more then one cylinder that is closed at a time.

The good thing about starting fluid is that it will evaporate quickly. After your done it’s always good to pull the plugs and let the starter run for a few seconds.

2 use the alternator nut to spin over the motor. The tension on the belt should be enough to help the motor spin over.

Also if you could take a picture of the damaged intake manifold. I believe I saw a part split in etka

#3

It’s all so simple and intuitive, once you’ve been told how :slight_smile:

Thanks mate! I’ll give it a shot.

Going to post up a how-to regarding manifold removal, for posterity.

#4

does anyone use gasoline (left for a few hrs) to soften up the carbon? It would be a natural fit, no?

#5

I’ll try it side by side with the decarb fluid and report back.

#6

Thanks. It would be cool to see the full documentation on what you had to do to take the intake apart and what was in there. You might be able to salvage the intake and not have to spend almost 2000 on a new one.

#7

Too late :frowning:

I was going to crack it open last night, but for my neighbours sake I stopped (I’m sure hammers and impact guns at midnight are not appreciated)

In the end I decided that even if I could fix it, I couldn’t trust it to not break again. So I spent on a new one from Jim Ellis last night ($1722 USD).

I took pics of the process of removal and will document the manifold disassembly, too. Basically, there are screws and glue/sealant. I’ve got the screws out, but I will have to be careful to break the sealant without cracking the manifold.

#8

Guys, I tried the petrol and the decarb solution today.

I will post up some pics in my decarb thread when I get to it- however,

The petrol did work somewhat, but I must say it’s not as strong at cleaning compared to the decarb fluid.

I first took the intake port dividers and put 5 in petrol and 5 in the decarb fluid. With some gentle agitation, the decarb cleaned up the loose deposits, whereas the petrol needed a brush to get there.

Since it worked pretty well, I filled the intake ports with petrol, and let them sit for about an hour, and from time to time worked at them with a toothbrush and beaker brush. When I removed the petrol, a lot of the really caked on deposits remained at the base of the valve.

I’ve left them in decarb fluid tonight and we’ll see how it goes tomorrow.

I can forsee the main problem being the removal of the liquid sludge now in there.

#9

OK - it seems I have reached the end of the road with the decarb fluid today.

It gets most of the stuff off, but there are some stubborn bits still left there which I can’t get off with a toothbrush and a lot of scrubbing. I have left the fluid soaking there for two days now.

I don’t want to scratch anything in there unnecessarily by using screwdrivers or other metal implements.

At this point I don’t know whether to look for a rotary tool with a flexible extension & stainless/nylon brush, or just grab a bag of walnut blasting medium and a blasting gun (already have the compressor & shop vac).

Any advice??

#10

I think guys are using a bunch of zip ties bundled together. Here are some pics that Jimmybones posted

http://i284.photobucket.com/albums/ll37/Jimmybones777/038969.jpg

http://i284.photobucket.com/albums/ll37/Jimmybones777/038968.jpg

They also bundle a whole bunch of them to the end of a drill as another tool for the cleaning (sorry, cant find a pic at the moment)

#11

I have used brass gun cleaning brushes they work great. Also a little tip after get most of it clean spray just a little mist of oil in each cylinder port and then go back and wipe with a clean cloth or paper towel. I know a few guys used oven cleaner and it really takes off the stubborn stuff.

#12

Over cleaner - good idea!

I’ll try these various solutions and report back.

Still proving difficult to remove the carbon which has turned to sludge. Too thick to vacuum up, and too thin to grab with pliers etc!

#13

*Oven

OT: Is there a way to edit posts on this forum?

#14

Ok, nothing works as well as the oven cleaner! Got some in my eyes, though… ugh.

And, even with the oven cleaner, you still need to scrub the very edges/corners of the valves. I had to use a rotary tool, and hack up the handle on the extension so it would fit in at the right angles.

I bet walnut blasting would have been much easier, but in the end I could not find any media in Australia.

I’ll put all of this together in my other thread Part 2.

#15

If the oven cleaner was helpful give CV a thanks he showed me and everyone from what I know about it. I found it works the best.