"Pete C." wrote in message
ster.com...

RBM wrote:

"Gary H" wrote in message
m...
Today I passed an auto parts store advertising "diesel exhaust fluid".
Does anyone know what that is?

It is liquid urea. All 2010 and newer diesel engines in the U.S. must
produce near zero emissions. To do this there are currently two methods.
One
method requires a wicked expensive filter, which, if it goes bad will
cost
the vehicle owner in the neighborhood of 3 thousand dollars, plus it
jacks
up the initial cost of the vehicle. The other method uses a separate tank
of
liquid urea, DEF, and injects it into the exhaust pipe causing a chemical
reaction with the exhaust gases effectively neutralizing them. Currently
it's really expensive, but ultimately It'll probably cost around $3 per
gallon. On an average sized vehicle a five or six gallon tank should last
for around 16000 miles.

Slight correction, 2007+ diesels have diesel particulate filters (DPF),
2010+ diesels have the UREA injection and selective catalyst reduction
*in addition* to the DPF. The UREA injection and SCR is supposed to also
help reduce the particulate generation so the DPF doesn't fill up and
require regeneration as often, but the DPF is still there. The DPFs are
also more like $1200 or so, not $3k, and the UREA is under $3/gal
already.

I'm not sure how other manufacturers are doing it, but Sprinters have two
separate types of systems. The earlier 2007-2009 use particulate filters,
and the 2010 began using Adblu urea and don't have particulate filters. In
the Sprinter blog there are several posts from members that have paid $3000
for particulate filter replacement. They also talk about having them cleaned
for $500. As far as the price of Def, two weeks ago I needed some and the
best I was able to get it for was $10 a gallon. I'm told Mercedes gets $20,
so I didn't feel too bad. Here's a site that explains the Sprinter systems:
http://www.ourexcellentadventures.co...inter-engines/