Cooling System (Lf, L3): Diagnosis Mazda 3 BL

ENGINE COOLANT LEVEL INSPECTION [LF, L3]

Note. If the "FL22" mark is shown on or near the cooling system cap, use FL22 type engine coolant. FL22 type engine coolant is shipped as a diluted solution (55% coolant, 45% water). Use the solution as is when replacing coolant.

1. Verify that the engine coolant level in the coolant reserve tank is between the MIN and MAX marks.
2. If the engine coolant level is below MIN mark, add engine coolant.

Scheme 2

Scheme 3

1. Measure the coolant temperature and specific gravity using a thermometer and a hydrometer. CAUTION: Use engine coolant at a concentration that meets the environmental conditions in which the vehicle is driven, otherwise engine damage could occur. The engine has aluminum parts and must be protected by an ethylene-glycol-based coolant to prevent corrosion and freezing. Do not use coolants containing Alcohol, Methanol, Borate or Silicate. These coolants could damage the cooling system. Use only soft (demineralized) water in the coolant mixture. Water that contains minerals will cut down on the coolant's effectiveness. Engine coolant damages paint. If engine coolant does get on a painted surface, rinse it off quickly. NOTE: If the "FL22" mark is shown on or near the cooling system cap, use FL22 type engine coolant. FL22 type engine coolant is shipped as a diluted solution (55% coolant, 45% water). Use the solution as is when replacing coolant.
2. Determine the coolant protection level by referring to the graph shown. If the coolant protection level is not correct, add water or coolant.

ENGINE COOLANT LEAKAGE INSPECTION [LF, L3]

Scheme 4

1. Inspect the engine coolant level.
2. Remove the cooling system cap.
3. Clean the installation parts of the cooling system cap.
4. Install the SST or aftermarket equivalent and a radiator cap tester to the coolant reserve tank filler port.
5. Apply pressure using the radiator cap tester. CAUTION: Applying more than 145 kPa {1.5 kgf/cm 2 , 21 psi} can damage the hoses, fittings, and other components, and cause leakage. Pressure 145 kPa {1.5 kgf/cm 2 , 21 psi} [1 min]
6. When pressurizing the coolant reserve tank, verify that the pressure is maintained. If the gauge needle drops, it may indicate water leakage. Repair or replace the applicable part.

COOLING SYSTEM CAP INSPECTION [LF, L3]

Scheme 5

1. Clean the cooling system cap and the sealed part.
2. Inspect the cooling system cap for cracks or everted seal. If there is any malfunction, replace the cooling system cap.
3. Attach the cooling system cap to the radiator cap tester.
4. Hold the cooling system cap downward and apply pressure gradually. Verify that the pressure holds for 10 s. If the pressure is not held stable within the specification, replace the cooling system cap. Pressure 135-155 kPa {1.38-1.58 kgf/cm 2 , 19.6- 22.4 psi}

THERMOSTAT INSPECTION [LF, L3]

1. Inspect the thermostat for the following. WARNING: During inspection, the thermostat and water are extremely hot and can cause severe burns. Do not touch the thermostat and water. The valve should not open under normal temperature. Opening temperature and valve lift If there is a malfunction, replace the thermostat. THERMOSTAT SPECIFICATIONS Item Specification Initial-opening temperature (°C {°F}) 80-84{176-183} Full-open temperature (°C {°F}) 97 {207} Full-open lift (mm {in}) 8.0 {0.31} or more

COOLING FAN MOTOR COMPONENT INSPECTION [LF, L3]

1. Perform the cooling fan control system inspection. (See «ENGINE CONTROL SYSTEM OPERATION INSPECTION [LF, L3]»(ref-345223-S18848681752009102000000) .) If the cooling fan control does not operate properly, inspect the following. ECT sensor A/C switch A/C refrigerant pressure switch (High/low pressure) A/C refrigerant pressure switch (Middle pressure) VSS A/C magnetic clutch Fan control module power supply circuit Fan control module ground circuit Fan control signal circuit (between fan control module terminal B and PCM terminal 1Y (California emission regulation applicable model), 1W (Except for California emission regulation applicable model with LF ATX), 1R (Except for California emission regulation applicable model with LF MTX, L3)) If the all items are normal, replace the cooling fan component.

Scheme 6

1. Drain the engine coolant. (See «ENGINE COOLANT REPLACEMENT [LF, L3]»(ref-345218-S35273147202009102000000) ).
2. Loosen the radiator drain plug completely.
3. Using a flathead screwdriver or equivalent, pry out the radiator drain plug. CAUTION: Do not apply excessive force to the flathead screwdriver or equivalent as doing so can damage the drain bore. Slowly and carefully pry out the radiator drain plug when removing it.
4. Install a new radiator drain plug with a new O-ring. Tightening torque 1.2-1.5 N.m {13-15 kgf.cm, 11-13 in.lbf}
5. Add engine coolant. (See «ENGINE COOLANT REPLACEMENT [LF, L3]»(ref-345218-S35273147202009102000000) ).