2009 GMC YUKON HYBRID coolant level

A. See “Engine Air Cleaner/Filter” in the owner manual.
B. Drive Motor/Generator Control Module (DMCM).
SeeDrive Motor/Generator Control Module (DMCM)
Cooling System on page 5-6.
C. Engine Oil Dipstick. See “Engine Oil” in the owner
manual.
D. Automatic Transmission Fluid Dipstick. See
Automatic Transmission Fluid on page 5-5.
E. Brake Fluid Reservoir. SeeBrakes on page 5-11.
F. See “Underhood Fuse Block” in the owner manual.
G. See “Windshield Washer Fluid” in the owner
manual.
H. Hybrid Auxiliary Fuse Block. SeeUnderhood Fuse
Block on page 5-22.
I. DMCM Coolant Surge Tank Pressure Cap. See
Drive Motor/Generator Control Module (DMCM)
Coolant Surge Tank Pressure Cap on page 5-6.
J. See “Coolant Surge Tank Pressure Cap” in
the owner manual.
K. Engine Oil Fill Cap. See “Engine Oil” in the owner
manual.Automatic Transmission Fluid
For more information, see “Automatic Transmission
Fluid” in the owner manual Index.
Checking the Fluid Level
Your vehicle’s automatic transmission dipstick looks like
this. For more information on location, seeEngine
Compartment Overview on page 5-4.
5-5

When you decide it is safe to lift the hood, here is what
you will see:
A. Drive Motor/Generator Control Module (DMCM)
B. Engine Coolant Surge Tank Pressure Cap
C. DMCM Coolant Surge Tank/Engine Coolant
Surge Tank
D. DMCM Cooling Hoses (Out of View)
E. DMCM Coolant Tank Pressure Cap
If the coolant inside the DMCM coolant surge tank is
boiling, do not do anything else until it cools down.The coolant level should be at or above the FULL
COLD mark with the vehicle parked on a level surface.
If it is not, there might be a leak at the DMCM cooler
core, DMCM pressure cap, DMCM cooler hoses,
DMCM cooling pump or somewhere else in the DMCM
cooling system.
Notice:Running the engine when there is a leak in
the hybrid cooling system can cause the hybrid
cooling system to lose all coolant and can damage
the system. Get any leak xed before you drive
the vehicle or run the engine.
5-7

{CAUTION:
You can be burned if you spill coolant on hot
engine parts. Coolant contains ethylene glycol
and it will burn if the engine parts are hot enough.
Do not spill coolant on a hot engine.
If the DMCM coolant is empty, your vehicle must be
serviced by your dealer and a special fill procedure
must be followed.
Notice:Attempting to ll the DMCM cooling surge
tank yourself when the uid level is empty can
damage your vehicle. Your vehicle must be serviced.1. Park the vehicle on a level surface and turn the
vehicle off. Remove the DMCM coolant surge
tank pressure cap when the DMCM cooling system,
including the DMCM coolant surge tank pressure
cap and DMCM cooling hoses, are no longer hot.
Turn the DMCM coolant surge tank pressure cap
slowly counterclockwise (left) about one full turn.
Wait 30 seconds.
5-9

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.
5-10