Air Bleeding Of Cooling System; Gas Leakage Test - Mitsubishi 6M60-TL Service Manual

GENERAL INSPECTION AND ADJUSTMENT

2. Air Bleeding of Cooling System

• With the pressure cap removed and the coolant temperature at 90°C, let the engine idle in order to bleed air com-
pletely out of the cooling system.
• After air bleeding is completed, refill the reservoir tank with coolant as needed.

3. Gas Leakage Test

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• Presence of air or exhaust gas in coolant accelerates corrosion
of the cooling system components. To prevent this, carry out air/
gas leakage tests in accordance with the following procedure.
• Remove the pressure cap.
WARNING
• If the engine is hot, boiling coolant may spurt out from the
filler port when the pressure cap is loosened. To avoid burn-
ing yourself, make sure to remove the pressure cap only
when the coolant is cold.
• Run the engine until the coolant temperature rises to approxi-
mately 90°C.
• If air bubbles appear continuously through the filler port, there is
air or exhaust gas penetrating into the cooling system.
• Presence of air in coolant can be an indication of loose cylinder
head bolts, loose water pump mounting bolts, loose hose con-
nections, and/or a damaged hose.
• Presence of exhaust gas in coolant can be an indication of a
damaged cylinder head gasket and/or cracks in the cylinder
head.