a4qtr

Hi there,

I am looking for fuel additives to clean out the carbon deposit buildups inside the combustion chambers. Any suggestion or recommendation on brands?

Stevelev

I've been told nothing will clean the deposits ... period. You gotta pull off the mani and scrape away the carbon or bring the car in for a proper cleaning. Apparently avoiding ethanol, using a catch can and driving it like you stole it will help reduce deposits ... Amazing the benefit of a proper cleaning had on my RS4 !

Ab-nrml aspir8d

There is a thread on the vortex in the Ontario section regarding engine cleaner for carbon build-up.
Try the Motul engine cleaner, and install a catch can in FSI motors ASAP.
These are direct injection engines and thus do not benefit from the fuel cleaning/lubricating the intake track. Catch cans virtually eliminate these issues.

The last time I was there, Euroline Performance have FSI specific catch can kits with all the fittings etc that are easy to install.

Stevelev

Do you know of any documented proof of this ? The reason I have not bnothered going with a catch can on my TTS is due to the lack of evidence reflecting this. I recall reading about a guy with an RS4 who still had buildup after a cleaning and installing a catch ...

a4qtr

What would they do for "a proper cleaning?" How much would that cost?

Stevelev

I had mine done under warranty (seems I have a horeshoe up my butt!). I've heard the cost is somewhere between $500. and $1,000. and the time would be dependant upon the number of cylinders. My dealership has a method of blasting walnut shells but many have scraped the deposits off the intake valves etc. If you go to the RS4 forum on Audizine, there are lost of threads on this and many with pics.

Cheers !

adamstasiak

Add Techron from Chevron to your gas. It will clean it to pure metal.
You probably need to bottles. The car will lose performance during the process but you will clean that carbon.
I do not recommend cleaning the carbon unless when you turn the car off it still runs for a second or two.
Some carbon is good for the engine since it seals the leaks of pressure and makes the rings on the pistons fit snuggly. When you clean the carbon the engine will be noisier for a long time.

mikeh

Should pay attention to Stevelev on this one. The RS4 he had with FSI (fuel stratified injection) is prone to carbon build up. I understand that the A4s with FSI are not so prone (why, perhaps Stevelev can answer).

There are plenty of claims by product manufactures that their product will remove carbon build up. The only way I know that you can adequately remove carbon is by physically doing so. Using non ethanol fuel like Shell 91 will reduce the carbon build up.

Drive it like you stole it once in a while is what was suggested.

Stevelev

Thanks mikeh! I understand the new Audi engines are all prone to carbon buildup (as well as Porsche one); however, a 10-15% loss of power over time is far more noticeable on a 420 hp RS than on a 210HP A4 ...

hoeser

This will not work for anything above the cylinders, pistons, and rings. Direct injection means just that, direct. The valve opens and fuel is shot directly into the cylinder, the only thing that ends up back in the manifold are exhaust gasses which are the source of the trouble in the first place. While this additive may work great in a traditional fuel injection system (where the valvetrain is bathed in fuel) it will not do anything for an FSI engine.

My 07' 3.2 A4 has 72,100km on the odometer and I'm starting to wonder if its getting to be about time for a proper cleaning. I'm getting a bit of a fuely smell on startup, no misfire codes yet though. Power seems to still be there. If you stand on it it definitely puffs a bit of carbon.