G 2500 3/4 Ton Van V8-305 5.0L VIN M SFI (1997)
Coolant: Testing and Inspection
Checking the Coolant
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If possible, first check the side of the coolant recovery reservoir to determine coolant level. If unreadable, the reservoir cap should be removed to
check coolant level. Check the coolant level in the recovery reservoir every time the hood is up and the engine coolant is cold. The level should be
near the "Cold" mark when the system is cold. At normal operating temperature, the coolant level should rise. Coolant should be added only to the
recovery reservoir to raise level to the "Cold" mark.
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While draining the system, check the color of the coolant. If the coolant shows an unusual amount of oil sediment (gray, white, or foamy
appearance) engine oil may be leaking into the cooling system. A coating of oil on the inside of the coolant passages cuts down the efficiency of
the system and may cause engine overheating. Also, a leak in the cooling system may cause coolant to flow into oil passages, contaminating the
lubricant and damaging the engine. Check oil condition no level.
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If pressure in the cooling system is too low, or if the coolant does not contain ethylene glycol antifreeze, the coolant will boil without the "TEMP"
indicator lamp coming on. Pure water could boil at 119°C (247°F) and the "TEMP" indicator lamp would not come on, even with a 124 kPa (18
psi) cooling system. Pure water lacks the necessary rust inhibitors and coolant pump lubricant. The engine should never be operated without the
pressure cap, Of with the cap loose, unless performing work on the cooling system, as the coolant will boil before the "TEMP" indicator lamp
comes on.
