INSTALLATION
MANUAL
© Scania CV AB 2018, Sweden
Changes from the previous issue
01:07 Issue 17 en-GB 3
Changes from the previous issue
The changes made in this document compared with the previous issue are marked
with a line in the left-hand margin. The changes are also described below.
• Information about Stage V engines has been added.
• The illustration in section Drain hole
for the reductant tank has been corrected.
• The illustration in section Connection of reductant doser
for Stage IV/Tier 4f and
Stage III B/Tier 4i has been corrected.
SCR and reductant
SCR (Selective Catalytic Reduction) is a system in which reductant is added to the
exhaust gases in order to reduce the nitrogen oxide (NO
x
) content. This document de-
scribes SCR system components and how they should be connected.
Reductant is a solution consisting of urea and water, and is usually called AdBlue®,
DEF, ARLA 32 eller AUS 32, depending on the market. If the engine is equipped
with an SCR system, the reductant is added to the exhaust gases upstream of the cat-
alytic converter. This reduces nitrogen oxide emissions.
Reductant in accordance with ISO 22241 contains 32.5% by weight of urea and
freezes at approximately -11°C (12°F). When the solution freezes, ice and urea al-
ways maintain the same concentration. Always store reductant at a temperature be-
tween -11°C and 30°C (12-86°F).
In order for the emission control to meet the emission requirements set by the public
authorities, the reductant should be specified in accordance with ISO 22241.
Cleanliness is very important when working on the reductant circuit. Clean thorough-
ly around all parts to prevent dirt from entering the system.
When working on the SCR system, the reductant connections may only be lubricated
with soapy water or with distilled water with a 3% urea mixture. Any other types of
lubricants may block and damage the components in the SCR system.
Reductant is highly corrosive. For this reason, only pipes and couplings resistant to
urea may be used in the SCR system. Always rinse away reductant spillage on con-
nections and other parts with lukewarm water to prevent corrosion. If reductant seeps
into electrical connections or electrical cables, these must be renewed.
Vibration limits
The components in the SCR system, including the oxidation catalytic converter,
evaporator, hydrolysis catalytic converter, SCR catalytic converter and reductant
tank, may not be exposed to vibration levels above 3.0 g in the frequency range 8-
500 Hz, if they are not engine-mounted.
The installation contractor must install the SCR components in such a way that they
are exposed to as little vibration from the surroundings as possible. This applies to
e.g. vibrations caused by the firing order, timing gear or road. Resonant frequencies
under 300 Hz must be avoided. Scania refers to ISO standard 16750 for more infor-
mation on vibrations.
Rec. % by weight of urea Limit values according to ISO 22241
32.5% 31.8-33.2%
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