INTERNAL LEAKAGE INSPECTION
Remove the engine oil pan drain plug and drain a small amount of engine oil. If coolant is present in the pan, it will drain first because it is heavier than oil. An alternative method is to operate engine for a short period to churn the oil. After this is done, remove the engine dipstick and inspect for water globules. Also inspect the transmission dipstick for water globules and transmission fluid cooler for leakage.
| WARNING | With radiator pressure tester tool installed on radiator, do not allow pressure to exceed 145 kPa (21 psi). Pressure will build up quickly if a combustion leak is present. To release pressure, rock tester from side to side. When removing tester, do not turn tester more than 1/2 turn if system is under pressure. |
Operate the engine without the pressure cap on the radiator until the thermostat opens. Attach a Pressure Tester to the filler neck. If pressure builds up quickly it indicates a combustion leak exists. This is usually the result of a cylinder head gasket leak or crack in engine. Repair as necessary.
If there is not an immediate pressure increase, pump the Pressure Tester. Do this until indicated pressure is within system range of 110 kPa (16 psi). Fluctuation of the gauge pointer indicates compression or combustion leakage into cooling system.
Because the vehicle is equipped with a catalytic converter, do not short out cylinders to isolate compression leak.
If the needle on dial of the pressure tester does not fluctuate, race engine a few times to check for an abnormal amount of coolant or steam. This would be emitting from exhaust pipe. Coolant or steam from exhaust pipe may indicate a faulty cylinder head gasket, cracked engine cylinder block or cylinder head.
COMBUSTION LEAKAGE TEST - WITHOUT PRESSURE TESTER
DO NOT WASTE reusable coolant. If the solution is clean, drain the coolant into a clean container for reuse.
| WARNING | Do not remove cylinder block drain plugs or loosen radiator draincock with system hot and under pressure. Serious burns from coolant can occur. |
Drain sufficient coolant to allow thermostat removal. Refer to THERMOSTAT, REMOVAL . Remove accessory drive belt. Refer to BELT, SERPENTINE, REMOVAL .
Add coolant to radiator to bring level to within 6.3 mm (1/4 in) of the top of the thermostat housing.
| CAUTION | Avoid overheating. Do not operate engine for an excessive period of time. Open draincock immediately after test to eliminate boil over. |
Start engine and accelerate rapidly three times, to approximately 3000 RPM while observing coolant. If internal engine combustion gases are leaking into cooling system, bubbles will appear in coolant. If bubbles do not appear, internal combustion gas leakage is not present.
DIAGNOSIS AND TESTING - COOLANT CONCENTRATION TESTING
Check coolant concentration when any additional coolant is added to the system, or after a coolant drain, flush and refill. Use of a hydrometer or Refractometer Tool (special tool #8286, Refractometer), refractometer can be used to test coolant concentration.
A hydrometer tests the amount of glycol in a mixture by measuring the specific gravity of the mixture. The higher the concentration of ethylene glycol, the larger the number of balls that will float, and the higher the freeze protection (up to a maximum of 60% by volume glycol).
A Refractometer Tool (special tool #8286, Refractometer) tests the amount of glycol in a coolant mixture by measuring the amount a beam of light bends as it passes through the fluid.
Some coolant manufacturers use other types of glycols into their coolant formulations. Propylene glycol is the most common new coolant. However, propylene glycol based coolants do not provide the same freezing protection and corrosion protection and are not recommended.
| CAUTION | Do not mix types of coolant - corrosion protection will be severely reduced. |
DIAGNOSIS AND TESTING - ENGINE BLOCK HEATER
If the unit does not operate, possible causes can be either the power cord or the heater element. Test the power cord for continuity with a 110-volt voltmeter or 110-volt test light. Test heater element continuity with an ohmmeter or a 12-volt test light.
| CAUTION | To prevent damage, the power cord must be secured in it's retainer clips and away from any components that may cause abrasion or damage, such as linkages, exhaust components, etc. |