Diagnosis; Thermostat Test; Surge Tank Cap Test - Daewoo Nubira User Manual

DIAGNOSIS

THERMOSTAT TEST

1. Remove the thermostat from the vehicle. Refer to
"Thermostat" in this section.
2. Make sure the valve spring is tight when the ther-
mostat is fully closed. If the spring is not tight, re-
place the thermostat.
3. Suspend the thermostat and a thermometer in a
pan of 50/50 mixture of ethylene glycol and water.
Do not let the thermostat or the thermometer rest
on the bottom of the pan because the uneven con-
centration of heat on the bottom could result in in-
accurate temperature measurements.
4. Heat the pan on a burner.
5. Use the thermometer to measure the temperature
of the heated solution.
6. The thermostat should begin to open at 87³C
(189³F) and it should be fully open at 102³C
(216³F). If it does not open at these temperatures,
replace the thermostat.

SURGE TANK CAP TEST

Tools Required
KM–471 Adapter
The surge tank cap maintains proper pressure, protects
the system from high pressure by opening a pressure
valve, and protects the coolant hoses from collapsing be-
cause of a vacuum.
1. Wash any sludge from the surge tank cap and the
valve seat of the vacuum pressure valve for the
surge tank cap.
DAEWOO V–121 BL4
ENGINE COOLING 1D – 3
2. Check for any damage or deformity to the vacuum
pressure valve for the surge tank cap. If any dam-
age or deformity is found, replace the cap.
3. Install a suitable cooling system pressure tester to
the cap using the adapter KM–471.
4. Pull the vacuum pressure valve open. If the surge
tank cap does not seal properly, replace the surge
tank cap.
5. Pressurize the cap to 90 to 120 kPa (13.1 to 17.4
psi).
6. Wait 10 seconds and check the pressure held by
the tank cap tester.
7. If the pressure held by the cooling system pressure
tester falls below 80 kPa (11.6 psi), replace the
surge tank cap.