water pump GMC YUKON HYBRID 2009 Owners Manual

Drive Motor/Generator Control
Module (DMCM) Coolant Surge Tank
Pressure Cap
SeeEngine Compartment
Overview on page 5-4
for more information
on location.
The Drive Motor/Generator Control Module (DMCM)
coolant surge tank pressure cap must be fully installed
on the hybrid coolant surge tank.
Notice:If the pressure cap is not tightly installed,
coolant loss and possible damage to the Drive
Motor/Generator Control Module (DMCM) may occur.
Be sure the cap is properly and tightly secured.
Drive Motor/Generator Control
Module (DMCM) Cooling System
In addition to the regular cooling system, the vehicle is
also equipped with a cooling system for the DMCM
system. This system is serviced differently than
the vehicle’s main cooling system. The DMCM cooling
system includes the DMCM coolant surge tank,
DMCM surge tank pressure cap, DMCM cooling pumps,
hybrid cooling radiator and the Drive Motor/Generator
Control Module (DMCM). The DMCM cooling system
uses a 50/50 pre-mixed DEX-COOL™ coolant and
deionized water available at your dealer/retailer.
See “Engine Coolant” and “Cooling System” in the
owner manual for more information.
5-6

2. Then keep turning the DMCM coolant surge tank
pressure cap slowly, and remove it.
3. Add the pre-mixed DEX-COOL™, available at your
dealer/retailer, to the DMCM coolant surge tank
until the level reaches the FULL COLD mark.
4. Turn the ignition to ON/RUN without starting the
engine. The hybrid cooling pumps will run and
any trapped air will purge to the surge tank.5. Add the pre-mixed DEX-COOL™, available at your
dealer/retailer, until the coolant level is maintained
at the FULL COLD mark. This should take no
longer than two minutes of hybrid cooling pump
operation.
If the level cannot be kept at the FULL COLD
level, your vehicle may need service. See your
dealer/retailer.
6. Then replace the
DMCM coolant surge
tank pressure cap.
Be sure the pressure
cap is hand-tight
and fully seated.
Notice:Using tap water, cooling system sealers or
conditioners in an attempt to stop coolant leaks
can damage the DMCM and engine cooling systems.
Never use tap water, cooling system sealers or
conditioners in your cooling system.
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