This is the first direct injection car for me.
I know that the H247 guys have nothing to worry about, as Mercedes installed port injectors as well as direct injectors.
So what do we do?
What did guys with high mileage do?
I didn't see anything in the service table, but I think nobody, no manufacturer, makes any acknowledgement that there is a problem, for legal reasons, by inserting a valve cleaning requirement.
So with this, I know that BMW had something with wallnut blasting, etc.
Did anybody check with the dealer?
So again, my prior life in the mazdaspeed world serves well.
Seafoam ingestion was all the rage after the issue was discovered. various techniques with "popping the blue clip vaccum line" and using an intermittent aspiration technique while idling to create clouds of white smoke, followed by some crappy response for a mile or so.
after a couple gurus dis seafoam, then a teardown, with pics, in a writeup, did it become apparent that any liquid cleaning was an absolute snake oil gig. the carbon is formed at such temp that it will barely soften with overnite soaks.
but soften it did, and the intake is on the front, and while the PS pump does needs to be swung over a bit, getting the intake mani off, and having direct visiulization of the stems got to be an hour or so, depending on prior mods.
for a short time, spraying, and scrubbing with various shapes of .22 cal bore brushes was in style.
ugh is right
then some brave soul collected wifes beach towels and blue painters tape, figured out the 2 spots of crank rotation that were right, and got hot with a harbor freight sandblaster, and harbor freight walnut shells. clean 4 valves, vacuum the surgical area clear, Retape, and rotate, Blast away at the other 4 valves, vaccum, wipe, De tape, and undrape the OR (it gets everywhere).
reassemble, and all set
the pristine, bare metal from head to guide, whole pocket, its just an awsome before and after pic on one that has alot of highway cruising miles.
So, to sum up
ONLY direct mechanical action will remove the deposits
many of the nasty solvents will soften the bonds in the gunk.
they accumulate over time in proportion to the running you do fully warmed up, ant part throttle
the source is the oil vapor recovery system, which commonly is routed back to the intake manifold for emmision reasons. How this is piped, routed, etc would have a great impact on formation the routing changes from boost to off boost, for ex. , but as long as oily vapor hits that hot metal, with nothing rinsing as it forms, you gonna get crudded up.
I did 4 MZR's its kinda an every 6th oil change thing.
the Audi guys have been down the same path,
Its gonna suc, real bad, at a AMG dealer for this, as a service