2007 GMC SIERRA CLASSIC check engine

3. With your foot on the brake pedal, run the
engine for at least once minute and shift to
DRIVE (D). Then shift to NEUTRAL (N) and
then REVERSE (R) to ll the hydraulic system.
Then, position the shift lever in PARK (P).
4. Allow the engine to run at idle (500–800 rpm).
Slowly release the brake pedal.
Then, without shutting off the engine, follow
these steps:
Cold Check Procedure
The purpose of the cold check is to determine if the
transmission has enough uid to be operated safely
until a hot check can be made. The uid level rises
as uid temperature increases. Do not ll above the
COLD CHECK band if the transmission uid is
below normal operating temperatures.
1. 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.
3. Check the uid level reading. Repeat the
check procedure to verify the reading.4. If the uid level is within the COLD CHECK
band, the transmission may be operated until
the uid is hot enough to perform a hot
check. If the uid level is not within the COLD
CHECK band, add or drain uid as necessary
to bring the level into the middle of the
COLD CHECK band.
5. Perform a hot check at the rst opportunity
after the normal operating temperature of
160°F (71°C) to 200°F (93°C) is reached.
6. If the uid level is in the acceptable range,
push the dipstick back in all the way.
495

Automatic Transmission Fluid
(Except Allison Transmission
®)
When to Check and Change Automatic
Transmission Fluid
A good time to check your automatic transmission
uid level is when the engine oil is changed.
Change the uid and lter at the intervals listed in
Additional Required Services (Gasoline Engine)
on page 621, and be sure to use the transmission
uid listed inRecommended Fluids and
Lubricants on page 629.
How to Check Automatic Transmission
Fluid
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 uid can
damage your transmission. Too much can
mean that some of the uid could come out
and fall on hot engine parts or exhaust system
parts, starting a re. Too little uid could
cause the transmission to overheat. Be sure
to get an accurate reading if you check
your transmission uid.
Wait at least 30 minutes before checking the
transmission uid level if you have been driving:
When outside temperatures are above
90°F (32°C).
At high speed for quite a while.
In heavy traffic — especially in hot weather.
While pulling a trailer.
To get the right reading, the uid should
be at normal operating temperature, which is
180°F to 200°F (82°C to 93°C).
Get the vehicle warmed up by driving about
15 miles (24 km) when outside temperatures are
above 50°F (10°C). If it is colder than 50°F (10°C),
drive the vehicle in THIRD (3) until the engine
temperature gage moves and then remains steady
for 10 minutes.
497

A cold uid check can be made after the vehicle
has been sitting for eight hours or more with
the engine off, but this is used only as a reference.
Let the engine run at idle for ve minutes if
outside temperatures are 50°F (10°C) or more. If it
is colder than 50°F (10°C), you may have to idle
the engine longer. Should the uid level be
low during this cold check, you must check the
uid hot before adding uid. Checking the uid hot
will give you a more accurate reading of the
uid level.
Checking the Fluid Level
Prepare your vehicle as follows:
1. Park your vehicle on a level place. Keep the
engine running.
2. With the parking brake applied, place the shift
lever in PARK (P).
3. 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).
4. Let the engine run at idle for three minutes
or more.Then, without shutting off the engine, follow
these steps:
The transmission
dipstick handle with this
graphic is located at
the rear of the engine
compartment, on
the passenger’s side
of the vehicle.
SeeEngine Compartment Overview on page 480
for more information on location.
1. Flip the handle up and then 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.
498

Manual Transmission Fluid
When to Check Manual Transmission
Fluid
A good time to have your manual transmission
uid checked is when the engine oil is changed.
SeeAdditional Required Services (Gasoline
Engine) on page 621to nd out when to change
your transmission uid.
How to Check Manual Transmission
Fluid
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.
Notice:Too much or too little uid can
damage your transmission. Too much can
mean that some of the uid could come out
and fall on hot engine parts or exhaust system
parts, starting a re. Too little uid could
cause the transmission to overheat. Be sure to
get an accurate reading if you check your
transmission uid.Check the uid level only when your engine is off,
the vehicle is parked on a level place, and the
transmission is cool enough for you to rest your
ngers on the transmission case.
Then, follow these steps:
1. Remove the ller plug.
2. Check that the lubricant level is up to the
bottom of the ller plug hole.
3. If the uid level is good, install the plug and be
sure it is fully seated. If the uid level is low,
add more uid as described in the next steps.
5-speed for VORTEC™ 4300 V6 and 4800 V8 engines
shown, other manual transmissions similar
500

How to Add Manual Transmission Fluid
Here is how to add uid. Refer to the Maintenance
Schedule to determine what kind of uid to
use. SeeRecommended Fluids and Lubricants on
page 629.
1. Remove the ller plug.
2. Add uid at the ller plug hole. Add only
enough uid to bring the uid level up to
the bottom of the ller plug hole.
3. Install the ller plug. Be sure the plug is fully
seated.
Hydraulic Clutch
The hydraulic clutch linkage in your vehicle is
self-adjusting. The clutch master cylinder reservoir
is lled with hydraulic clutch uid.
It is not necessary to regularly check clutch uid
unless you suspect there is a leak in the system.
Adding uid will not correct a leak.
A uid loss in this system could indicate a
problem. Have the system inspected and repaired.
When to Check and What to Use
The clutch master
cylinder reservoir is
located in the rear of the
engine compartment on
the driver’s side of the
vehicle. SeeEngine
Compartment Overview
on page 480for more
information on location.
Refer to the Maintenance Schedule to determine
how often you should check the uid level in
your clutch master cylinder reservoir and for the
proper uid. SeeOwner Checks and Services
on page 625andRecommended Fluids and
Lubricants on page 629.
501

How to Check and Add Fluid
The proper uid should be added if the level does
not reach the bottom of the diaphragm when it
is in place in the reservoir. See the instructions on
the reservoir cap.
Engine Coolant
The cooling system in your vehicle is lled with
DEX-COOL®engine coolant. This coolant is
designed to remain in your vehicle for ve years
or 150,000 miles (240 000 km), whichever
occurs rst, 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, seeEngine
Overheating on page 505.A 50/50 mixture of clean, drinkable water and
DEX-COOL
®coolant will:
Give freezing protection down
to−34°F (−37°C).
Give boiling protection up to 265°F (129°C).
Protect against rust and corrosion.
Help keep the proper engine temperature.
Let the warning lights and gages work as they
should.
Notice:Using coolant other than DEX-COOL
®
may cause premature engine, heater core,
or radiator corrosion. In addition, the engine
coolant may require changing sooner, at
the rst maintenance service after each
30,000 miles (50 000 km) or 24 months,
whichever occurs rst. Any repairs would not
be covered by your warranty. Always use
DEX-COOL
®(silicate-free) coolant in your
vehicle.
502

What to Use
Use a mixture of one-half clean, drinkable water
and one-half DEX-COOL®coolant which will
not damage aluminum parts. If you use this coolant
mixture, you do not need to add anything else.
{CAUTION:
Adding only plain water to your cooling
system can be dangerous. Plain water, or
some other liquid such as 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 would
not get the overheat warning. Your engine
could catch re 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 would not 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 extra inhibitors and/or
additives in your vehicle’s cooling system,
you could damage your vehicle. Use only the
proper mixture of the engine coolant listed
in this manual for the cooling system.
SeeRecommended Fluids and Lubricants
on page 629for more information.
503

Checking Coolant
The coolant surge tank is located in the engine
compartment on the passenger’s side of the
vehicle. SeeEngine Compartment Overview on
page 480for more information on location.
{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.
If your vehicle is equipped with a low coolant
sensor and the LOW COOLANT LEVEL message
comes on and stays on, it means you are low
on engine coolant. See “LOW COOLANT LEVEL”
underDIC Warnings and Messages on page 270.
504