Lee,
This has been discussed on many forums recently. Basically as I
understand it, it summarizes as this: the new ULSD fuel has less
lubricity, less aromatics and less fuel efficiency.
Less lubricity for the older engines (defined in this case as
pre-2007) means you *will* need to find a good additive package. One
inexpensive way to add lubricity is to add plain old ATF (automatic
transmission fluid) at each fill up. I have seen many different
estimates of how much, everywhere from 1qt to 1gal per 100 gallons of
fuel. Mike H., one of the forum's resident diesel gurus, even
mentioned up to 5% ATF, which seems pretty high to me. Check with
truck stops to see if any commercial additive packages for the ULSD
have hit their shelves yet. While there are claims that fuel
manufacturers have added additional lubricity additive packages to the
ULSD, one of our Lone Star Birds members who owns a heavy diesel
repair shop has said fuel pump manufacturers were recommending adding
lubricity additives even with the previous LSD fuel or they would not
warrant the pumps. In any event, it seems clear that you will need a
lubricity agent to be safe.
Less aromatics means less seal swelling which may translate into fuel
leaks on some engines. A high pressure fuel leak on a hot engine is
something I plan to keep a good eye out for when I have to start
buying the ULSD (still have LSD available around here so far in spite
of deadlines). I have heard rumors that some Mercedes and Cummins
forums have already reported fuel leaks as a problem, but that could
be more good old internet urban legends than fact. Find a discussion
group specific to your engine, but watch your individual engine to be
sure.
Less fuel efficiency in the neighborhood of 1.2% has been reported
(see
http://www.nrc.gov/reading-rm/doc-collec...20062\
2.pdf)
At my fuel inefficiency of about 5-5.5mpg, a 1.2% decrease appears to
be rounding error from my standpoint and something I can't much fret
over. Points one and two are much more significant to me in terms of
potentially disasterous results and long term engine wear.
Something that has not been reported or discussed on the forums is how
the new EPA laws have also affected lubricating oils. The new
"CJ"-rated diesel engine oil spec was specifically designed for the
2007 ULSD engines. It also has reduced sulfur as well as phosphorous
and sulfated ash which helps stabilize the oil's TBN (total base
number), acts as a lubricity agent and provides alkalinity to
counteract acid formation during combustion. My understanding is that
oil manufacturers can not maintain the TBN with current additive
packages. All of this taken together may result in reduced ability to
neutralize blow-by which creates more sulpheric acid which in turn
creates corrosion, more deposits which could clog piston rings and
cause cylinder wall scuffing, less total wear protection for the
engine, etc, etc...... While oil ratings are generally rated as
backwards compatible (CI vs. CD, etc.), I noted some engine oil
manufacturers recommending to use the CJ oils only in the new (2007+)
heavy duty engines and stick with the older rated oils for older heavy
duty diesel engines. In my opinion, you really need to be sure you
are sticking with a CI rated oil for older (pre-2007) engines. As
time goes on, and the over the road fleets mature into a predominance
of 2007+ engines, the older oil formulations will probably be harder
to come by.
Just my understanding. Not a fuel or oil manufacturer, but grew up in
the fuel distribution business and have maintained an interest in what
is really going in my engines.
FWIW, etc, etc....
Mike Bulriss
1991 WB40 "Texas Minivan"
San Antonio, TX
--- In
WanderlodgeForum@yahoogroups.com, "Lee Davis"
wrote:
>
> I have a 95 BMC with the 300 Cummins diesel engine. I am full time now
> on the West Coast and of course all you can get now is the new fuel.
> Should I be adding something when I fill up or is it OK for the older
> engines? If I should be using an additive, what is recommended and
> where do you get it?
>
> Lee Davis
>