This has been discussed at length in the past. The 4.7 does not "foam" the
oil or get moisture in the oil more than any other engine. What it DOES have
is an oil filler neck that allows the emulsified oil to catch up in there,
yet is not right on the valve cover where it gets heated back up and allowed
to "boil" back away as fast as other engines.
Every internal combustion engine has to allow the crankcase to breath
outside air in and out of it during operation. In a humid environment it is
taking in humidity in this process. If you take any car you have and drive
it only 3 or 4 miles when it is cool and the humidity is high, pull over and
shut it off, then look at the underside of your oil filler cap you will have
some of the grey schmutz there. Drive another 10 miles and it will most
likely be gone after reaching full operating temp for a while. The filler
neck on the 4.7 sits at the top front of the engine, right in the direct
flow of the cooling air, and stands up from the engine to boot. This tends
to keep it from getting hot eough to "cook off" the moisture in the oil at
that spot only. So then it has become more noticable. Chryslers fix was to
put a baffle in to prevent excessive amounts of this getting to the top of
the neck and being "seen". Which is an adequate fix as far as I'm concerned
since all engines exibit this behaviour, It's just that the 4.7 shows it off
too much....
I live in Phoenix and the only time I've seen this on my 4.7 was when I
checked while camping in the north country in the winter here. Otherwise
there's never enough humidity for it to happen. The same "foaming" would be
present on the filler caps of all my previous cars, some of which moved here
to AZ with me. The issue dissapeared on those cars when I came to this hot
dry climate.
YMMV
Tim Koth
2K CC 4X4 4.7 5spd
----- previous posts -----
> The 4.7's foaming is no huge deal, as far as I know. From what I
> understand, a little bit of moisture gets under the oil fill cap, and it
> emulsifies in the oil in the valvetrain, and I guess makes little
> bubbles, which go up the filler tube. It's been discussed extensively
> in the archives. Also take a look at:
> http://faq.dakota-truck.net/Engine/4.7_foamy_oil.html
Moisture in your fluids isn't good, from what I understand (Tom & Jon,
butt out! :))
I checked my oil fill cap ('03 4.7) and don't have the little dongle;
the fill tube isn't a straight shot, it's almost funnel-like. I can
take a picture but not sure how it'll come out.
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