1999 CADILLAC DEVILLE engine

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6-16
Engine Air Cleaner/Filter
The engine air cleaner/filter is located next to the
windshield washer fluid reservoir on the driver's side of
the engine. Be sure the engine has cooled before
following these steps to replace the air cleaner filter:
1. Disconnect the Intake
Air Temperature (IAT)
sensor from the base of
the air cleaner.
2. With a screwdriver,
loosen the air duct
clamp, which is located
at the mass airflow
sensor end of the
air duct.
3. Disconnect the air duct from the mass airflow sensor.

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6-18
Follow these steps to reinstall the air cleaner assembly:
1. Slide the air cleaner lid into the slots in the front
edge of the air cleaner base.
2. Pivot the air cleaner cover and the air duct assembly
downward. Make sure that both latches are secure
and fully engaged.
3. Reinstall the clean air duct over the mass airflow
sensor. Make sure that the duct is secure around the
entire outer edge of the sensor.
4. Tighten the air duct clamp.
5. Reconnect the IAT sensor.
Refer to the Maintenance Schedule to determine when to
replace the air filter.
See ªScheduled Maintenance Servicesº in the
Maintenance Schedule booklet.
CAUTION:
Operating the engine with the air cleaner/filter
off can cause you or others to be burned. The air
cleaner not only cleans the air, it stops flame if
the engine backfires. If it isn't there, and the
engine backfires, you could be burned. Don't
drive with it off, and be careful working on the
engine with the air cleaner/filter off.
NOTICE:
If the air cleaner/filter is off, a backfire can cause
a damaging engine fire. And, dirt can easily get
into your engine, which will damage it. Always
have the air cleaner/filter in place when
you're driving.

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6-19
Automatic Transaxle Fluid
When to Check and Change
A good time to check your automatic transaxle fluid
level is when the engine oil is changed.
Change both the fluid and filter every 50,000 miles
(83 000 km) if the vehicle is mainly driven under one or
more of these conditions:

In heavy city traffic where the outside temperature
regularly reaches 90F (32C) or higher.

In hilly or mountainous terrain.

When doing frequent trailer towing.

Uses such as found in taxi, police or delivery service.

Use such as limousine service.
If you do not use your vehicle under any of these
conditions, the fluid and filter do not require change
until the message CHANGE TRANS FLUID appears on
the Driver Information Center.
See ªScheduled Maintenance Servicesº in the
Maintenance Schedule booklet.
How to Check
Because this operation can be a little difficult, you may
choose to have this done at the dealership service department.
If you do it yourself, be sure to follow all the
instructions here, or you could get a false reading on
the dipstick.
NOTICE:
Too much or too little fluid can damage your
transaxle. Too much can mean that some of the
fluid could come out and fall on hot engine parts
or exhaust system parts, starting a fire. Be sure to
get an accurate reading if you check your
transaxle fluid.
Wait at least 30 minutes before checking the transaxle
fluid level if you have been driving:

When outside temperatures are above 90F (32C).

At high speed for quite a while.

In heavy traffic
-- especially in hot weather.

While pulling a trailer.

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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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6-23
Engine Coolant
The cooling system in your vehicle is filled with
DEX
-COOL
engine coolant. This coolant is designed
to remain in your vehicle for 5 years or 150,000 miles
(240 000 km), whichever occurs first, if you add only
DEX
-COOL
extended life coolant.
The following explains your cooling system and how to
add coolant when it is low. If you have a problem with
engine overheating, see ªEngine Overheatingº in
the Index.
A 50/50 mixture of clean, drinkable water and
DEX
-COOL
coolant will:

Give freezing protection down to
-34F (-37C).

Give boiling protection up to 265F (129C).

Protect against rust and corrosion.

Help keep the proper engine temperature.

Let the warning lights and gages work as
they should.
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.

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6-24 What to Use
Use a mixture of one-half clean, drinkable water and
one
-half DEX-COOL
coolant which won't damage
aluminum parts. If you use this coolant mixture, you
don't need to add anything else.
CAUTION:
Adding only plain water to your cooling system
can be dangerous. Plain water, or some other
liquid like alcohol, can boil before the proper
coolant mixture will. Your vehicle's coolant
warning system is set for the proper coolant
mixture. With plain water or the wrong mixture,
your engine could get too hot but you wouldn't
get the overheat warning. Your engine could
catch fire and you or others could be burned. Use
a 50/50 mixture of clean, drinkable water and
DEX
-COOL
coolant.
NOTICE:
If you use an improper coolant mixture, your
engine could overheat and be badly damaged.
The repair cost wouldn't be covered by your
warranty. Too much water in the mixture can
freeze and crack the engine, radiator, heater core
and other parts.
If you have to add coolant more than four times a year,
have your dealer check your cooling system.
NOTICE:
If you use the proper coolant, you don't have to
add extra inhibitors or additives which claim to
improve the system. These can be harmful.

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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.