Cadillac XT4 Owner's Manual page 175

174 DRIVING AND OPERATING
Caution
Do not mix fuel with DEF, and do
not put DEF in the fuel tank. This
could lead to costly repairs that
might not be covered by the vehicle
warranty.
Diesel Exhaust Fluid (DEF) is used
with diesel engines to reduce the
amount of regulated emissions
produced. Products such as AdBlue
are types of DEF, and are approved for
use in the vehicle as long as they have
an API certification label or meet ISO
22241. The fluid level in the DEF tank
must be maintained for the vehicle to
run properly. DEF is not a fuel
additive. DEF should not be mixed
with or added to diesel fuel. DEF
freezes when exposed to temperatures
below 11 °C (12 °F). For DEF tank
capacity see Capacities and
Specifications 0 326.
It is normal to hear the DEF system
purge fluid back into the tank after
the vehicle is turned off.
Locating Diesel Exhaust Fluid
DEF can be purchased at your retailer.
Additionally, some diesel truck filling
stations or retailers may have DEF for
purchase. See Customer Assistance
Offices in the owner's manual for
phone numbers to assist in contacting
a GM retailer. See Recommended Fluids
and Lubricants 0 322.
Filling the DEF Tank
The blue DEF cap is behind the fuel/
DEF door. Do not remove the fuel and
DEF caps at the same time. Fill diesel
fuel and DEF independently. Turn the
DEF cap anticlockwise to remove.
In cold conditions DEF can freeze in
the DEF filler pipe opening. If this
prevents the filling of the DEF tank,
park the vehicle in a warm garage
overnight.