tjf

So if / when you have carbon buildup issue, how much does the cleaning procedure run on a V8?

jschrauwen

This has been covered extensively in other threads.
That said, prices vary depending on the process used - manual hand cleaning or walnut shell blasting.
Prices also vary according to location - EU vs US vs Canada, etc etc. (You did not state your location or the year of your 4.2L)

If this is for your A8L, are you sure it's the direct injection type? I thought the switch occurred in 06?

tjf

Not for my A8. That is not an FSI. I'm contemplating an S5. I know it's an issue with the 2011-2012's and one of the factors would be known upcoming costs.
I know it has been discussed, but a lot of the posts are older and not too many discuss cost. I saw $600 - $1000. I wasn't sure if cast had come down, or if they has been some more developments for methods or DIY kits.

jschrauwen

Carbon build-up and requisite carbon cleaning is not an S5 issue. It's a direct injection engine issue that has touched every manufacturer - Euro, USA, JDM, etc etc.

Look to 1:23 of the video.

pocketmaster

I did my own carbon cleaning using Walnut Shell Media blast. I already had a compressor, so I purchased a portable media blaster at Harbor Freight ($30) and the media from Harbor Freight ($25). I also ordered a VW Crankshaft Socket on Ebay ($25) so I could rotate the engine by hand. So for less than $100 I performed the job myself. Once the intake manifold is off and the runners, it's just a matter of media blasting the closed valves (cover the open valves with tape), rotate the engine to close the open valves and repeat the cleaning. Took roughly 8 hrs, but I'm very OCD and took my time.

jschrauwen

Thanks for that Chad. I was hoping the OP (Tom) would have mentioned where he lived as that can have a bearing on the cost factor.
Here in Ontario, Canada walnut shell blasting costs an average of between $600 to $900 depending on the number of cylinders with an average turn around time of about 4 hours.

No new revelations in the carbon cleaning process aspect. The UK seem to be high on this Hydro-Cleaning process but apparently that's more smoke and mirrors then anything else.
The media blasting (walnut shells or soda blasting) is probably the most thorough but there are shops that do do the hand manual cleaning using solvents, brushes, pics etc etc. No empirical proof one is better then the other, other then the pics of the before/after comparing both processes.
It is suggested in some circles to stave a subsequent carbon cleaning process, people are suggesting installing an oil catch can system. The details of how it works makes it a sound option as it is supposed to substantially extend the time period til the next time a carbon cleaning is needed. However, this catch can option should only be used in geographic areas where they don't see any substantial freezing during the winter months.
Of course, more frequent oil change intervals using a good Group IV oil along with using premium ethanol free gas and a daily does of an Italian Tune-up should also be helpful.

tjf

"I was hoping the OP (Tom) would have mentioned where he lived"
... Bluegrass region in KY. Although I do get up your way a couple of times a year. The in-laws have a place just north of Kingston.
I'm glad it can be done DIY, without too much difficulty (from the sound of it). I am surprised that no company has come up with a cleaning system, where you could inject solvents into the intake while the car is running. I know this is available to clean injectors, where the car is actually running on the solvent.

jschrauwen

Funny you should mention injecting something into the intake. Toyota and few other manufacturers have adopted supplemental fuel injectors into the intake plenum of their direct injected engines. Naturally they're of significant smaller cc size as injectors go but their purpose is basically to achieve what the old non direct injected engines did which was to wash fuel over the backs of the intake valves. This is supposed prevent any carbon build up - per-say.

BMW may have been the first to be proactive in the intake carbon cleaning process. They adopted the walnut shell blasting process as a BMW service which Audi has still failed to do. Audi still subscribes to some snake oil treatment plan that basically does little to nothing. BMW as taken the cleaning process one further and has adopted walnut shell carbon cleaning process as a scheduled service interval. Audi has nothing similar.

(I live an hour southwest of Kingston along the lake)

tjf

Don't the newer Audi engines have the port injector also ?

SloopJohnB@mac.com

A methanol/water injection system can work pretty well.

I stand corrected:

http://www.greencarcongress.com/2014...4014-audi.html

Still, I haven't seen one..... I doubt that it will come to the US. Here's Alex' take:

https://www.alexsautohaus.com/blog/v...nes-explained/


Google is your friend, BTW.