Cadillac 2005 CTS - Manual (Page 316)

3. Fill the coolant surge tank with the proper mixture,
to slightly above the FULL COLD/FROID line on
the side of the coolant surge tank.
4. With the coolant surge tank pressure cap off, start
the engine and let it run until you can feel the upper
radiator hose getting hot. The upper radiator
hose is the top hose coming out of the radiator, on
the passenger’s side of the vehicle. Watch out
for the engine cooling fans.
By this time, the coolant level inside the coolant
surge tank may be lower. If the level is lower, add
more of the proper mixture to the coolant surge tank
until the level reaches the FULL COLD/FROID
line on the side of the coolant surge tank.
5. Then replace the pressure cap. Be sure the
pressure cap is hand-tight and fully seated.
Start the engine and allow it to warm up. If the Check
Coolant Level message does not appear on the
Driver Information Center (DIC), the coolant is at the
proper fill level. If a Check Coolant Level message does
appear, repeat Steps 1 to 3 then reinstall the pressure
cap, or see your dealer.
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