THERMOSTAT
Most thermostats are thermal wax pellet type. As coolant temperatures rise the wax begins to expand. This expansion overcomes spring tension allowing the thermostat to open. Some thermostats also incorporate an additional bleed hole to allow a small amount of circulation and helps eliminate air locks.
PRESSURE CAP
Modern cooling systems use a closed system type cap. This system allows for coolant expansion during engine operation. As coolant expands and builds pressure, some coolant is permitted to bleed past the cap into the overflow tank. When the engine cools and coolant contracts, the cap allows the coolant in the overflow tank to siphon back into the system.
The pressure cap also increases pressure in the cooling system. The increased pressure raises the boiling point, one pound of pressure raises the boiling point approximately 10° F (12.2° C).
COOLANT MIXTURE
Engine coolant must be mixed with water to a specific percent. A 100% coolant mixture could cause system overheating or premature system failure. The percentage of coolant to water can vary depending on climate condition, but a 50/50 mixture is a standard percentage. Engine coolant should also include an aluminum protection additive. This will help protect against metal deterioration.
MAINTENANCE
Periodic maintenance is necessary for extended cooling system and engine life. Engine and cooling stems are made of different metals, electrolysis begins to destroy the metals. Changing the coolant at scheduled maintenance periods reduces electrolysis and removes sediment. See COOLANT REPLACEMENT SCHEDULE .
| Application | Months (Miles) |
|---|---|
| General Motors | 24 (30,000) |
COOLANT REPLACEMENT SCHEDULE
Note. Approximate capacity figures are shown. Capacities may vary 15% due to system variations.
| Application | Specification |
|---|---|
| Coolant Capacity | 15.3 Qts. (14.5L) |
| Pressure Cap | 15 psi |
| Thermostat | 195°F (91°C) |
COOLING SYSTEM SPECIFICATIONS
See also:
• COOLANT REPLACEMENT SCHEDULE