Daewoo NUBIRA, User Manual

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1D – 4 I ENGINE COOLING
DAEWOO V–121 BL4
COOLING SYSTEM DIAGNOSIS
Engine Overheats
Checks Action
Check for a loss of the coolant. Add the coolant.
Check for a weak coolant solution. Confirm that the coolant solution is a 50/50 mixture of eth-
ylene glycol and water.
Check the front of the radiator for any dirt, leaves, or in-
sects. Clean the front of the radiator.
Check for leakage from the hoses, the coolant pump, the
heater, the thermostat housing, the radiator, the core
plugs, or the head gasket. Replace any damaged components.
Check for a faulty thermostat. Replace a damaged thermostat.
Check for retarded ignition timing. Perform an PCM/ECM code diagnosis. Confirm the integ-
rity of the timing belt.
Check for an improperly operating electric cooling fan. Replace the electric cooling fan.
Check for radiator hoses that are plugged or rotted. Replace any damaged radiator hoses.
Check for a faulty water pump. Replace the faulty water pump.
Check for a faulty surge tank cap. Replace the faulty surge tank cap.
Check for a cylinder head or an engine block that is
cracked or plugged. Repair the damaged cylinder head or the damaged engine
block.
Loss of Coolant
Checks Action
Check for a leak in the radiator. Replace the damaged radiator.
Check for a leak in the following locations:
S
Surge tank.
S
Hose.
Replace the following parts, as needed:
S
Surge tank.
S
Hose
Check for loose or damaged radiator hoses, heater hoses,
and connections. Reseat the hoses.
Replace the hoses or the clamps.
Check for leaks in the coolant pump seal. Replace the coolant pump seal.
Check for leaks in the coolant pump gasket. Replace the coolant pump gasket.
Check for an improper cylinder head torque. Tighten the cylinder head bolts to specifications.
Replace the cylinder head gasket, if needed.
Check for leaks in the following locations:
S
Intake manifold.
S
Cylinder head gasket.
S
Cylinder block plug.
S
Heater core.
S
Radiator drain plug.
Repair or replace any components, as needed, to correct
the leak.
Engine Fails to Reach Normal Operating Temperature or Cool Air
from the Heater
Checks Action
Check to determine if the thermostat is stuck open or is the
wrong type of thermostat. Install a new thermostat of the correct type and heat range.
Check the coolant level to determine if it is below the MIN
mark on the surge tank. Add sufficient coolant to raise the fluid to the specified
mark on the surge tank.