1999 CADILLAC DEVILLE radiator cap

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5-13
NOTICE:
Engine damage from running your engine
without coolant isn't covered by your warranty.
See ªOverheated Engine Protection Operating
Modeº in the Index.
NOTICE:
When adding coolant, it is important that you use
only DEX
-COOL
(silicate-free) coolant.
If coolant other than DEX-COOL is added to the
system, premature engine, heater core or
radiator corrosion may result. In addition, the
engine coolant will require change sooner
-- at
30,000 miles (50 000 km) or 24 months,
whichever occurs first. Damage caused by the use
of coolant other than DEX
-COOL
is not
covered by your new vehicle warranty.
If there seems to be no leak, with the engine on, check to
see if the electric engine cooling fans are running. If the
engine is overheating, both fans should be running. If
they aren't, your vehicle needs service.
How to Add Coolant to the Coolant
Surge Tank
If you haven't found a problem yet, but the coolant level
isn't at the proper level (2.5 inches (6.4 cm) below the
base of the fill neck), add a 50/50 mixture of clean,
drinkable water and DEX
-COOL
coolant at the
coolant surge tank, but be sure the cooling system,
including the coolant surge tank pressure cap, is cool
before you do it. (See ªEngine Coolantº in the Index
for more information.)

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5-16
1. You can remove the coolant surge tank pressure cap
when the cooling system, including the coolant surge
tank pressure cap and upper radiator hose, is no
longer hot. Turn the pressure cap slowly
counterclockwise (left) until it first stops. (Don't
press down while turning the pressure cap.)
If you hear a hiss, wait for that to stop. A hiss means
there is still some pressure left.2. Then keep turning the cap, but now push down as
you turn it. Remove the pressure cap.

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5-17
3. Then fill the coolant surge tank with the proper
mixture, to the base of the filler neck.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. 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 about 2.5 inches (6.4 cm)
below the base of the filler neck.

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6-12 Checking Engine Oil
Pull out the dipstick and clean it with a paper towel or
cloth, then push it back in all the way. Remove it again,
keeping the tip down, and check the level.
When to Add Engine Oil
If the oil is at or below the ADD line, then you'll need
to add at least one quart of oil. But you must use the
right kind. This part explains what kind of oil to use. For
crankcase capacity, see ªCapacities and Specificationsº
in the Index.
NOTICE:
Don't add too much oil. If your engine has so
much oil that the oil level gets above the upper
mark that shows the proper operating range,
your engine could be damaged.
The oil fill cap is located
behind the radiator on the
passenger's side of the
engine. Turn the cap
counterclockwise to
remove it.
Be sure to fill it enough to put the level somewhere in
the proper operating range. Push the dipstick all the way
back in when you're through.

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6-20
To get the right reading, the fluid should be at normal
operating temperature, which is 180F to 200F
(82C to 93C).
Get the vehicle warmed up by driving about 15 miles
(24 km) when outside temperatures are above 50F
(10C). If it's colder than 50F (10C), you may have
to drive longer.
Checking the Fluid Level

Park your vehicle on a level place. Keep the
engine running.

With the parking brake applied, place the shift lever
in PARK (P).

With your foot on the brake pedal, move the shift
lever through each gear range, pausing for about
three seconds in each range. Then, position the shift
lever in PARK (P).

Let the engine run at idle for three to five minutes.Then, without shutting off the engine, follow these steps:
1. The black transaxle fluid cap is located next to the
radiator hose and below the air cleaner assembly on
the driver's side of the engine. Remove the air
cleaner assembly so you can reach the transaxle fluid
cap. The assembly is attached to the vehicle by two
fasteners. Lift up on the air cleaner assembly to
remove it. Find the transaxle fluid cap and turn it
counterclockwise to remove. Pull out the dipstick
and wipe it with a clean rag or paper towel.
2. Push it back in all the way, wait three seconds and
then pull it back out again.

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6-22 How to Reset Transaxle Fluid
Change Indicator
Your vehicle is equipped with a transaxle fluid change
indicator. A CHANGE TRANS FLUID message will
display on the Driver Information Center (DIC) when
the powertrain computer determines that the transaxle
fluid needs to be changed or at each 100,000 miles
(160 000 km) interval, whichever occurs first. When this
message appears, change the transaxle fluid and reset
the transaxle fluid life indicator as follows:
1. Turn the ignition on but do not start the engine.
2. Press and hold the OFF and rear defog buttons on the
climate control at the same time until the TRANS
FLUID RESET message appears on the DIC.
Surge Tank Pressure Cap
NOTICE:
The surge tank cap is a 15 psi (105 kPa)
pressure
-type cap and must be tightly installed to
prevent coolant loss and possible engine damage
from overheating. Be sure the arrows on the
cap line up.
If the surge tank pressure cap needs to be replaced, a
GM cap is recommended.
Thermostat
Engine coolant temperature is controlled by a thermostat
in the engine coolant system. The thermostat stops the
flow of coolant through the radiator until the coolant
reaches a preset temperature.
If your thermostat needs to be replaced, a GM
thermostat is recommended.

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6-25 Checking Coolant
The surge tank is located next to the engine block on the
passenger's side of the engine.
The cooling system is under a lot of pressure when it is
hot. If the CHECK COOLANT LEVEL message
appears on the Driver Information Center (DIC), you
will need to add coolant.
CAUTION:
Turning the surge tank pressure cap when the
engine and radiator are hot can allow steam and
scalding liquids to blow out and burn you badly.
Never turn the surge tank pressure cap
-- even a
little
-- when the engine and radiator are hot.
The vehicle must be on a level surface. When your engine
is cold, the coolant level should be at the full cold mark,
which is 2.5 inches (6.4 cm) below the base of the fill
neck. Use a flashlight as necessary to see into the tank.
If the CHECK COOLANT LEVEL message comes on
and stays on, it means you're low on engine coolant.
For more information, see ªCheck Coolant Level
Messageº in the Index.