My engine has high mileage, looking down the spark plugs holes there is clearly carbon on top of the pistons its a dark thick'ish coating, why would you want to get rid of carbon? Promotes detonation.

Now I'll put my flame suit on...

I dribbled water down the brake booster line as soon as it reached the intake manifold you could hear it turning to steam and probably expanding, I ran probably half a small cup into the vac line not rushing it and keeping the revs high. The exhaust onto a piece of paper expelled speckles still this may not have been carbon.

Result, well the top of the pistons have now a light brown coating instead of a dark black and this is when it was time to stop as I don't believe you should have no carbon. You can use sea foam which is probably stronger but I'd rather not have it eat away at seals.

I regularly change my oil so It seems regular oil changes and good fuel do not keep them crystal clean.

One word of caution you can hydro lock your engine if you put too much water in as obviously you can't compress water. You will foul your spark plugs a little, also a small amount of water can pass through an engine no problem. A concern of mine was dislodging chunks of carbon and them getting stuck and reducing the seals caused by carbon helping but I don't think it's strong enough. Checked the oil and there was a tiny tiny bit if mayo as to be expected.

 

I heard from someone with an Audi you can use a bag of sand connect it up to the intake tube to do port polish and clean up the carbon build up on the valve and piston too

 

Found the link, you should try this - http://www.audiforums.com/forum/off-...e-wrong-80267/

 

That's an old Internet joke its probably been on every car forum , obviously it doesn't work and will f@#k the engine.

I was skeptical Tbh but it appears to have removed some carbon, will I do it again, no, I was bored and intrigued .

 

BG 44K is supposed to clean carbon deposits from petrol engines

Has anybody tried it ?

I've only got 20k miles on mine so was thinking about using it as a preventative measure

Not too comfortable about dribbling water through the intake

As for the audi link judging from the grammer it sounds like the sort of thing your average audi driver would do

 

Good old redex usually does it, add a bottle to every tankfull for the next 3 or 4 tanks, do you always use optimax? I thought that kept carbon away

 

Yes, I've used it on a number of cars, including my S it works well. I even did a before and after endo check on a Mk4 Escort and was very impressed with the results.
On the S (31K on the clock at the time) it gave more pull and 3-4 mpg more for a while, I don't think the S was too bad in the first place but it did make a difference IMO.

 

I've tried bg44k in the past I checked the pistons like I did with this method, no difference. There's more difference when I did the water trick.

 

Water methanol is ment to be amazing at deep cleaning the engine.

 

Which is ? waiting too be flamed , use the search etc