CHEVROLET IMPALA 2005 8.G Owners Manual

If No Steam Is Coming From Your
Engine
An overheat warning along with a low coolant message
can indicate a serious problem.
If you get an engine overheat warning, but see or hear
no steam, the problem may not be too serious.
Sometimes the engine can get a little too hot when you:
Climb a long hill on a hot day.
Stop after high-speed driving.
Idle for long periods in traffic.
Tow a trailer.
If you get the overheat warning with no sign of steam,
try this for a minute or so:
1. In heavy traffic, let the engine idle in NEUTRAL (N)
while stopped. If it is safe to do so, pull off the road,
shift to PARK (P) or NEUTRAL (N) and let the
engine idle.
2. Turn on your heater to full hot at the highest fan
speed and open the windows as necessary.If you no longer have the overheat warning, you can
drive. Just to be safe, drive slower for about 10 minutes.
If the warning does not come back on, you can drive
normally.
If the warning continues, pull over, stop, and park your
vehicle right away.
If there is still no sign of steam, you can idle the engine
for three minutes while you are parked. If you still
have the warning, turn off the engine and get everyone
out of the vehicle until it cools down. Also, see
“Overheated Engine Protection Operating Mode” later
in this section.
You may decide not to lift the hood but to get service
help right away.
5-33

Overheated Engine Protection
Operating Mode
This emergency operating mode allows your vehicle to
be driven to a safe place in an emergency situation.
If an overheated engine condition exists, an overheat
protection mode which alternates ring groups of
cylinders helps prevent engine damage. In this mode,
you will notice a signicant loss in power and engine
performance. The low coolant light may come on
and the temperature gage will indicate an overheat
condition exists. Driving extended miles (km) and/or
towing a trailer in the overheat protection mode should
be avoided.
Notice:After driving in the overheated engine
protection operating mode, to avoid engine damage,
allow the engine to cool before attempting any
repair. The engine oil will be severely degraded.
Repair the cause of coolant loss, change the oil
and reset the oil life system. SeeEngine Oil
on page 5-18.
Cooling System
When you decide it is safe to lift the hood, here is what
you will see:
A. Engine Coolant Recovery Tank
B. Electric Engine Cooling Fans
C. Radiator Pressure Cap3400 V6 Engine
5-34

A. Engine Coolant Recovery Tank
B. Electric Engine Cooling Fans
C. Radiator Pressure Cap
{CAUTION:
An electric engine cooling fan under the hood
can start up even when the engine is not
running and can injure you. Keep hands,
clothing and tools away from any underhood
electric fan.
If the coolant inside the coolant recovery tank is boiling,
do not do anything else until it cools down. The vehicle
should be parked on a level surface.
The coolant recovery tank is located in the rear of the
engine compartment on the passenger’s side of the
vehicle. SeeEngine Compartment Overview on
page 5-12. 3800 V6 Engine shown, 3800 V6 Supercharged
Engine similar
5-35

To check the coolant level, look for the COLD mark on
the side of the coolant recovery tank that faces the
engine. When the engine is cold, the coolant level
should be at or above the COLD mark on the coolant
recovery tank. If it is not, you may have a leak at
the pressure cap or in the radiator hoses, heater hoses,
radiator, water pump, or somewhere else in the
cooling system.
{CAUTION:
Heater and radiator hoses, and other engine
parts, can be very hot. Do not touch them.
If you do, you can be burned.
Do not run the engine if there is a leak. If you
run the engine, it could lose all coolant.
That could cause an engine re, and you could
be burned. Get any leak xed before you drive
the vehicle.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 are not, your vehicle needs service.
Notice:Engine damage from running your engine
without coolant is not covered by your warranty.
SeeOverheated Engine Protection Operating Mode
on page 5-34for information on driving to a safe
place in an emergency.
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 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.
5-36

How to Add Coolant to the Coolant
Recovery Tank
If you have not found a problem yet, but the coolant
level is not at the COLD mark, add a 50/50 mixture of
clean, drinkable water and DEX-COOL
®engine
coolant at the coolant recovery tank. SeeEngine
Coolant on page 5-29.
{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:In cold weather, water can freeze and crack
the engine, radiator, heater core and other parts.
Use the recommended coolant and the proper
coolant mixture.
{CAUTION:
You can be burned if you spill coolant on hot
engine parts. Coolant contains ethylene glycol
and it will burn if the engine parts are hot
enough. Do not spill coolant on a hot engine.
When the coolant in the coolant recovery tank is at the
COLD mark, start your vehicle.
5-37

If the overheat warning continues, there is one more
thing you can try. You can add the proper coolant
mixture directly to the radiator, but be sure the cooling
system is cool before you do it.
{CAUTION:
Steam and scalding liquids from a hot cooling
system can blow out and burn you badly.
They are under pressure, and if you turn the
radiator pressure cap — even a little — they
can come out at high speed. Never turn the
cap when the cooling system, including the
radiator pressure cap, is hot. Wait for the
cooling system and radiator pressure cap to
cool if you ever have to turn the pressure cap.
How to Add Coolant to the Radiator
Notice:Your engine has a specic radiator ll
procedure. Failure to follow this procedure could
cause your engine to overheat and be severely
damaged.
1. You can remove the radiator pressure cap when
the cooling system, including the radiator pressure
cap and upper radiator hose, is no longer hot.
Turn the pressure cap slowly counterclockwise until
it rst stops. Do not 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.
5-38

2. Then keep turning the pressure cap, but now push
down as you turn it. Remove the pressure cap.
{CAUTION:
You can be burned if you spill coolant on hot
engine parts. Coolant contains ethylene glycol
and it will burn if the engine parts are hot
enough. Do not spill coolant on a hot engine.
3. If you have the 3800 V6 engine, remove the
3800 Series II V6 engine cover shield to access
the bleed valve.
3.1. Clean the area around the engine oil ll tube
and cap before removing. Twist the oil ll
tube, with cap attached, counterclockwise
and remove it.
3.2. Lift the engine cover shield at the front, slide
the catch tab out of the engine bracket and
remove the cover shield.
3.3. Put the oil ll tube, with cap attached, in the
valve cover oil ll hole until you are ready to
replace the cover shield.
5-39

4. After the engine cools, open the coolant air bleed
valve or valves.
3400 V6 engine: There are two bleed valves.
The rst is located on the thermostat housing.
The second is located on the thermostat bypass
tube, on top of the water pump housing.3800 V6 engine: There is one bleed valve. It is
located on the thermostat housing. 3400 V6 Bleed Valve #1
3400 V6 Bleed Valve #23800 Series II V6 Bleed Valve
5-40

5. Fill the radiator with the proper DEX-COOL®
coolant mixture, up to the base of the ller
neck. SeeEngine Coolant on page 5-29for more
information about the proper coolant mixture.
If you see a stream of coolant coming from an
air bleed valve, close the valve. Otherwise,
close the valves after the radiator is lled.
6. Rinse or wipe any spilled coolant from the engine
and the compartment.7. If you have the 3800 V6 engine, replace the
3800 Series II V6 engine cover shield.
7.1. Remove the oil ll tube, with cap attached,
from the valve cover.
7.2. Insert the catch tab on the cover shield
under the bracket on the engine.
7.3. Place the hole in the cover shield over the
hole in the valve cover. Install oil ll tube and
cap by twisting clockwise.
8.
Then ll the coolant recovery tank to the COLD mark.
9. Put the cap back on the coolant recovery tank,
but leave the radiator pressure cap off.
5-41

10. Start the engine and let it run until you can feel the
upper radiator hose getting hot. Watch out for the
engine cooling fans.11. By this time, the coolant level inside the radiator
ller neck may be lower. If the level is lower, add
more of the proper DEX-COOL
®coolant mixture
through the ller neck until the level reaches
the base of the ller neck.
12. Then replace the pressure cap. At any time during
this procedure if coolant begins to ow out of the
ller neck, reinstall the pressure cap. Be sure
the arrow on the pressure cap lines up properly.
13. Check the coolant in the recovery tank. The level in
the coolant recovery tank should be at the HOT
mark when the engine is hot or at the COLD mark
when the engine is cold.
5-42