Honda Civic Hybrid 2009 Owner's Manual page 340

If the Engine Overheats
5. Look for any obvious coolant leaks,
such as a split radiator hose.
Everything is still extremely hot,
so use caution. If you find a leak, it
must be repaired before you
continue driving (see Emergency
Towing on page 345 ).
6. If you don't find an obvious leak,
check the coolant level in the
radiator reserve tank (see page
258 ). Add coolant if the level is
below the MIN mark.
7. If there was no coolant in the
reserve tank, you may need to add
coolant to the radiator. Let the
engine cool down until the reading
reaches the middle of the
temperature gauge or lower
before checking the radiator.
334
Removing the radiator cap
while the engine is hot can
cause the coolant to spray out,
seriously scalding you.
Always let the engine and
radiator cool down before
removing the radiator cap.
Using gloves or a large heavy
8.
cloth, turn the radiator cap
counterclockwise, without pushing
down, to the first stop. After the
pressure releases, push down on
the cap, and turn it until it comes
off.
Start the engine, and set the
9.
interior temperature to maximum.
Add coolant to the radiator up to
the base of the filler neck. If you
do not have the proper coolant
mixture available, you can add
plain water. Remember to have
the cooling system drained and
refilled with the proper mixture as
soon as you can.
10. Put the radiator cap back on
tightly. Run the engine, and check
the temperature gauge. If it goes
back to the red mark, the engine
needs repair (see Emergency
Towing on page 345 ).
11. If the temperature stays normal,
check the coolant level in the
radiator reserve tank. If it has
gone down, add coolant to the
MAX mark. Put the cap back on
tightly.