Chrysler 2.7L engine problems, why?

[Bryan]

I've read a lot about 2.7L engines failing due to the oil
forming sludge. Has it been determined what causes the
sludge to form?

 

[Bill Putney]

I've read a lot about 2.7L engines failing due to the oil
forming sludge. Has it been determined what causes the
sludge to form?

I've never seen anything definitive on that, and Chrsyler certainly
isn't going to discuss it. I have a theory that it has to do with
return drain passages being too small, so the sump starves for oil, and
that this is due to some concept that keeping those passages small helps
with some emissions issues in some 3rd or 4th order kind of way. Some
late model Toyota and Honda engines have the same problem, which leads
me to believe that there's some common design philosophies with some
unanticipated problems that have worked their way into several engine
designs. It may be too that the problem is marginal in that it may not
manifest itself with perfect maintenance, but the slight bit of neglect
(oil changes, severe driving schedules, etc.) will result in excessive
sludge, whereas if everything is done perfectly (oil changes on time,
highway driving vs. short, stop and go trips, etc) may keep the issue
below the damage levels.

Using Marvel Mystery Oil or Sea Foam would be extra insurance against
the tendency in these engines. Some say that they would never put any
oil additives in an engine. My reponse is that generally speaking, I
would not put a tourniquet on my leg either, but if it's a choice
between bleeding to death and possibly losing a leg, or, the alternative
(i.e., dying), I will use the tourniquet and live to fight another day.
8^)

Bill Putney
(to reply by e-mail, replace the last letter of the alphabet in my
address with "x")