Carbon cleaning without intake manifold removal

[Jaffs]

I've done a tonne of reading about decarbonising the inlet on my GTI and was resigned to the fact that the intake manifold would have to come off to do it properly.

Has anyone ever tried this company out? https://carboncleaningaustralia.com/

No intake manifold removal to clean up the intake by about 75 % using hydrogen to convert the carbon to hydrocarbons that burn off. Seems pretty good to me, considering my only symptom so far is a cold start misfire. There are different stages, with stage 3 being the most you can do with a petrol direct injection motor - for $275 is seems worth a shot.

[Lucas_R]

I used a similar company who did a 1 hour hydrogen treatment to my diesel engine and a few months later i removed the intake and it was full of carbon. The car only had done approx 35,000km at the time. When you see the carbon you will understand that no spray chemical will remove it - its pretty hard and very sticky.

I use carby cleaner which is good to loosen it up and then you need to scrape it off using picks/screwdrivers/nylon interior trim removal tools etc. Paint thinners apparently works well also but ive never used it. I did try petrol however and it was crap. So carby cleaner is what i use.

Engine Carbon Clean NSW - Home

This guy I used mainly does the "stage 2" treatments which is approx $900 (that was a verbal quote he gave me) and involves removing the intake manifold, egr, intake pipes etc cleaning all of the parts in a ultrasonic cleaning bath so they look like new again.

The "stage 2" treatment is ultimately what my engine needed so the stage 1 did basically nothing. So i did the equivalent of stage 2 myself for a few hours of my time and a few cans of carby cleaner.

[Jaffs]

Thanks so much for your response. Did it make any noticeable difference having it done and would you know if a diesel motor is any worse to clean using this technique than a petrol motor?

I just really cbf removing the intake mani, but I don't want a placebo effect either, where nothing actually gets cleaned for the money spent. I've got 123K on the clock and feel that it's about time that something needs doing (plus there seems to be the inevitable water pump/thermostat housing leak, albeit a very slow one - like less than 1 L of premix coolant added in 40K/2.5 years of driving).

As an aside, there's a solvent called trichloroethylene, which is magic for removing crud. Wouldn't surprise me if that's in some carby cleaners.

[Lucas_R]

Diesels are probably worse than your Mk6 GTI for carbon buildup due to the EGR system. My car had a good 5-6mm of carbon with only 35,000km. Crazy! Pics here:Playing with an Audi SQ5 TDI

The reason I got it done was because shortly after buying the car I code P2006 error which is a code for a stuck intake manifold runner flap. I bought the car with 28,000km on it so no idea how it was driven prior to my ownership. It had full service history but I bought it through a dealer so I never met the original owner. I can only assume it did a lot of idling and short drives at low rpm to have that much buildup. The car was from Melbourne so lots of stop/start traffic also no doubt.

At 35,000km is when I got the error. So I got the hydrogen clean done and error cleared, then a month or so later the error came back. Thats when I decided to remove the intake parts myself and have a look. I couldn't believe how much carbon was in there with such a low kilometre engine. Once I cleaned it properly I never got the error code again. Shortly after doing the clean I fitted up a catch can (which is a very necessary item on a diesel engine).

I have done the clean again about a year ago (car now has 70,000km) and it was nowhere near as dirty as the first time. The catch can and also (i can only assume) the way I drive the car has made a drastic difference. It was also much easier to clean the 2nd time around (was much less sticky).

I used to have a Mk6 GTI and i used to use the LiquiMoly intake cleaner every 6 months before an oil change. Nulon etc also make their own version of the intake cleaner. Its just a spray that I used to apply via the PCV hose which unclips off the passenger side of the inlet manifold. Engine must be running at about 2000rpm so you need a second person to help. Im not sure how much (if anything) it does, but for $30 and 15 mins of your time it might be worth a try. I used to do it for preventative measures only as my GTi was low km's and didnt have any misfires.

This is the one I used to use: Liqui-Moly Petrol Engine Intake Decarb - 366g | Supercheap Auto

[Jaffs]

Champion, thanks for the informative reply Lucas. The amount of carbon in those pics is insane for only 35K.