DEF Components and Piping
DEF Precautions
If the DEF tank needs to be repositioned, refer to the following illustrations for coolant flow. Due to its corrosive nature, diesel
exhaust fluid requires special considerations around electrical systems.
CAUTION
Urea solution is hazardous for open electrical connectors and spreads rapidly in cables. If urea is spilled on a connector,
the part of the cable that has been exposed to urea solution must be exchanged immediately.
W2105885
W2105581
W2105865
1. Coolant From Engine
2. Coolant to the DEF Return
3. Excess DEF Return (from DEF pump during normal pres-
sure cycles and key off cycles)
4. DEF to DEF Pump (then from the DEF pump to the DEF
Injector)
5. Power
The DEF pump unit sits inside the DEF tank
Mack Body Builder Instructions
CHU, CXU, GU, TD, MRU, LR
USA139046859
Date 5.2017
Body Builder; Engine, MP7, MP8, and MP10
Page 40 (43)
All Rights Reserved
