Re: [Chrysler300] Pinging & carbon buildup

["Warren R Anderson" <wranderson@xxxx>]

Carbon buildup on intake valve stems is a serious problem which seems to be
modern fuel technology related. I reference fuel injected engines of
computer controlled variety. Excessive carbon deposits absorb fuel. This
will cause poor cold start performance, general rough running and failed
emission tests. There are products on the market to fix computer cars with
carbon buildup (on valve stems and in the combustion chamber) and these
methods and materials also work on pre computer engines.

One such device is the first I remember and is now marketed by Snap-On
Tools. It was a good buy at $1500 with a bunch of adaptors but that was
before Snap-On took over and the same tool is now $4000 +. Oops, not for the
auto hobbyist. Carbon cleaning is a (necessary) service sold by many
professional shops as a fix it and as general routine maintenance for some
autos and especially in emissions non attainment areas where there is
emission inspection. You should be able to find a qualified shop and have
this done for you if you are apprehensive at all about pouring water in your
engine which does sound scary until you've been there and done it.

Point is, the equipment is expensive. We have noted in our shop that the
fluid used smells very strongly of acetic acid (vinegar) which a DeCarbon
rep acknowledged he thought was a very strong possibility. So, what we use
in place of $4K tools and magic elixer is water and vinegar. This mix does
work as does just straight water. We also use ACDelco X66-P carb tune-up
conditioner which I feel works best. Chrysler markets a combustion chamber
cleaner that is must do item for Jeep Eagle 6 cyl that had carbon/piston
interference problems if you didn't use the stuff. I've fixed Cadillac
knocking with Chrysler product. BTW water doesn't smoke like top engine
cleaners do, so if you have good neighbors, this might be a consideration.

An oil change would be recommended after water de carbon treatment.

Water injection kits were marketed (may still be but don't) for detonation
supression and these really cleaned out a combustion chamber. Remember how
clean a coolant leak into a cylinder leaves the piston and head? Pour away.
My experiences have been that it takes more than a little and this is why
the oil change recommendation BTW.

Warren Anderson
Sedona, AZ