1994 CHEVROLET CORVETTE engine overheat

Downloaded from www.Manualslib.com manuals search engine NOTICE:
If your engine catches fire because
you keep driving with no coolant,
your vehicle can be badly damaged.
The costly repairs would not be covered by your warranty.
If No Steam Is Coming from Your
Engine:
If you get the overheat warning but see 01
hear no steam, the problem may not be
too serious. Sometimes the engine can ge
a little too hot when you:
0 Climb a long hill on a hot day.
0 Stop after high speed driving.
0 Idle for long periods in traffic.
If you get the overheat warning with no
sign of steam,
try this for a minute or so:
1. Turn off your air conditioner.
2. Turn on your heater to full hot at the
highest fan speed and open the
window as necessary.
(Neutral).
3. If you’re in a traffic jam, shift to “N’
[f you no longer have the overheat
warning, you can drive. Just to be safe,
hive slower for about ten minutes. If the
warning doesn’t come back on, you can
drive normally.
[f the warning continues, pull over, stop,
and park your vehicle right away.
[f there’s still no sign of steam, you can
idle the engine for two or three minutes
while you’re parked, to see if the warning
stops. But then, if you still have
the
warning, TURN OFF THE ENGINE
AND GET EVERYONE OUT
OF THE
VEHICLE until it cools down.
You may decide not to lift the hood but to
get service help right away.
Cooling System
When you decide it’s safe to lift the hood,
here’s what you’ll see on the LTl engine:
1. Coolant recovery tank
2. Coolant high fill reservoir with
3. Electric engine fans
pressure cap
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Downloaded from www.Manualslib.com manuals search engine Problems on the Road
F
Cooling System
When you decide it’s safe to lift the hood,
here’s what you’ll see on the
LT5 engine:
1. Coolant recovery tank
2. Coolant high fill reservoir with
3. Electric engine fans
pressure cap
. . -152
If
the coolant inside the coolant recovery
tank is boiling, don’t do anything else
until it cools down.
When it is cool, remove the coolant
recovery tank cap and look at the dipstick.
The coolant level should be at or above
“COLD.” If it isn’t, you may have a leak
in the radiator hoses, heater hoses,
radiator, water pump or somewhere else
in the cooling system.
I NOTICE:
I
Engine damage from running your
engine without coolant isn’t covered
by your warranty.
If there seems to be no leak, check
to see
if the electric engine fans are running.
If the engine is overheating, both fans
should be running.
If they aren’t, your
vehicle needs service.

Downloaded from www.Manualslib.com manuals search engine How to Add Coolant to the Coolant
Recovery Tank
If you haven’t found a problem yet, but
the coolant level isn’t at or above the
“COLD, mark, add a
50150 mixture of
clean water (preferably distilled) and a
proper antifreeze at the coolant recovery
tank. (See “Engine Coolant” in the Index
for more information about the proper
coolant
mix.)
NOTICE:
I
In cold weather, water can freeze and
crack
the engine, radiator, heater core
and other parts. Use the recom-
mended coolant.
When the coolant in the coolant recovery
tank is at or above the
“COLD” mark,
start your vehicle.
If the overheat warning continues, there’s
one more thing you can try. You can add
the proper coolant mix directly to the
coolant high fill reservoir, but be sure the
cooling system is cool before you do it.
153 ...

Downloaded from www.Manualslib.com manuals search engine Problems on the Road
How to Add Coolant to the Coolant
High
Fill Reservoir - LT1 Only
NOTICE:
I
The LT1 engine (Code P) has a
specific coolant high fill reservoir
fill procedure. Failure to follow this
procedure could cause your engine to
overheat and be severely damaged.
1. You can remove the coolant high fill
reservoir pressure cap when the
cooling system, including the coolant
high fill reservoir pressure cap and
upper radiator hose,
is no longer hot. Turn the pressure cap slowly to
the
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.
. . .I54

Downloaded from www.Manualslib.com manuals search engine Service and Appearance Care
Remove the nut on the outboard side
of the unit. Then loosen the front and
inboard nuts. For the LT5 engine, loosen
the two inboard nuts. Move the ECM unit
to either side.
Fluid should be added if the fluid level
is at or below the “ADD” mark on the
reservoir. There are additional instructions
on the reservoir cap.
When returning the ECM to its proper
position, make sure the bolts are aligned
with the slots in the bracket. Then gently
push down on the unit. When replacing
the unit, be careful not to over-tighten the
nuts -just tighten them until they are
snug.
. . * 188
Rear Axle
When to Check Lubricant
Refer to the Maintenance Schedule
to determine how often to check the
lubricant. See “Periodic Maintenance
Inspections” in the Index.
How to Check Lubricant
If the level is below the bottom of the
filler plug hole, you’ll need to add some
lubricant. Add enough lubricant to raise
the level to the bottom of the filler plug
hole.
What to Use:
To add lubricant when the level is low, use
Axle Lubricant (GM Part
No. 12345977)
or
SAE 8OW-90 GL-5 gear lubricant.
To completely refill after draining,
add 4 ounces (1 18 ml) of Limited-Slip
Differential Lubricant Additive (GM Part
No. 1052358). Then fill to the bottom of
the filler plug hole with Axle Lubricant
(GM Part
No. 12345977) or SAE 8OW-90
GL-5 gear lubricant.
Engine Coolant
The following explains your cooling
system and how to add coolant when
it
is low. If you have a problem with
engine overheating or
if you need to add
coolant to your high fill reservoir, see
“Engine Overheating” in the Index.
The proper coolant for your Corvette will:
0
0
0
0
0
Give freezing protection down to -34°F (-37°C).
Give boiling protection up to 262°F
(128°C).
Protect against rust and corrosion.
Help keep the proper engine
temperature.
Let the warning lights work as they
should.

Downloaded from www.Manualslib.com manuals search engine What to Use:
Use a mixture of one-half clean water
(preferably distilled) and one-half
antifreeze that meets “GM Specification
1825-M,” which won’t damage aluminum
parts.
You can also use a recycled coolant
conforming to GM Specification 1825-M
with a complete coolant flush and refill.
If you use this mixture, you don’t need to
add anything else.
NOTICE:
If you use an improper coolant mix,
your engine could overheat and be
badly damaged. The repair cost wouldn’t be covered by your
warranty.
Too much water in the mix
can freeze and crack the engine,
radiator, heater core and other parts.
Adding Coolant
I’o Check Coolant When your engine is
;old, check the dipstick on the cap of the
;oolant recovery tank. The coolant level
should be at “COLD,” or a little higher.
When your engine is warm, the level on
the dipstick should be up to “HOT,” or a
little higher.
Your Corvette also has a coolant high fill
reservoir located at the right rear of the
engine compartment.
189 ...

Downloaded from www.Manualslib.com manuals search engine Service and Appearance Care
If you need to add more coolant, add the
proper mix at
the coolant recovery tank,
but only when your engine is cool. If the
tank is very low or empty, also add
coolant to the coolant high fill reservoir.
See “Engine Overheating”
in the Index
for information.
. . .190
Add coolant mix at the recovery tank, but
be careful not to spill it.
NOTICE:
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. Don’t
spill coolant on a hot engine.
For complete drain, flush and refill
of
the engine, contact your Chevrolet
jealer or the procedure may be found in
3 Chevrolet Corvette Service Manual. To
purchase a service manual, see “Service
Publications” in the Index.
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.
When you replace your thermostat, an
AC@ thermostat is recommended.

Downloaded from www.Manualslib.com manuals search engine Fuses and Circuit
Breakers
The wiring circuits in your vehicle are
protected from short circuits by a
combination of maxi-fuses, mini-fuses
and circuit breakers. This greatly reduces
the chance of fires caused by electrical
problems.
There are three fuse centers on your
vehicle. One
is in the right side of your
instrument panel. Turn the knob and pull
the door to access the fuses. The other
two fuse blocks are in the
engine compartment. One is part of the
Forward Lamp wiring harness
(A), and
the other is part of the ECM-Engine
wiring harness
(B).
Look at the silver-colored band inside
the fuse. If the band is broken or melted,
replace the fuse. Be sure you replace a
bad fuse with a new one of the correct
size.
If you ever have a problem on the road
and don’t have a spare fuse, you can
borrow one of the correct value. Just pick
some feature of your vehicle that you can
get along without
- like the radio or
cigarette lighter
- and use its fuse, if it
is the size you need. Replace it as soon
as you can.
Headlights
The headlight wiring is protected by a
circuit breaker
in the switch. An electrical
overload will cause the lights to go on and
off, or in some cases to remain
off. If this
happens, have your headlight wiring
checked right away.
Windshield Wipers
The windshield wiper motor is protected
by a circuit breaker and a fuse. If the
motor overheats due to heavy snow, etc.,
the wiper will stop until the motor cools.
If the overload is caused by some
electrical problem and not snow, etc.,
be sure to get
it fixed.
Power Windows and Other Power
Options
Circuit breakers protect the power
windows and other power accessories.
When the current load is too heavy,
the circuit breaker opens and closes,
protecting the circuit until the problem
is fixed or goes away.
II
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