Cooling System [2.5L]: Overview Mazda Tribute II

ENGINE COOLING DESCRIPTION AND OPERATION - 2.5L

Note. The addition of Cooling System Stop Leak Pellets darken coolant from yellow to golden tan.

The cooling system consists of the following components

1. Block heater (if equipped).
2. Radiator
3. Bypass tube
4. Pressure relief cap
5. Degas bottle
6. Radiator draincock
7. Coolant pump
8. Coolant temperature indicator sender unit
9. Thermostat housing

Engine coolant provides freeze protection, boil protection, cooling efficiency and corrosion protection to the engine and cooling components. In order to obtain these protections, the engine coolant must be maintained at the correct concentration and fluid level in the degas bottle.

When adding engine coolant, use a 50/50 mixture of engine coolant and distilled water.

Note. The addition of Cooling System Stop Leak Pellets darkens Mazda Premium Gold Engine Coolant from yellow to golden tan.

Use Mazda Premium Gold Engine Coolant or equivalent meeting Mazda Specifications (yellow color). Do not mix coolant types.

1. Do not add/mix orange-colored Mazda Specialty Orange Engine Coolant or equivalent meeting Mazda specifications or green colored Mazda Premium Engine Coolant meeting Mazda specifications or equivalent. Mixing coolants may degrade the coolant's corrosion protection.
2. Do not add alcohol, methanol, brine or any engine coolants mixed with alcohol or methanol antifreeze. These can cause engine damage from overheating or freezing.
3. Do not mix with recycled coolant unless it meets the requirements of Mazda specifications. Not all coolant recycling processes meet this Mazda specification. Use of such a coolant may harm the engine and cooling system components. Do not mix coolant types.

Note. Black arrows indicate hot, white arrows indicate cold.

Scheme 1

Principles of Operation

Engine coolant flows primarily from the engine to the radiator circuit and back to the coolant pump. From the coolant pump, coolant is sent through the engine block and cylinder heads. A separate circuit from the engine also feeds the heater core with coolant. The coolant pump is operated by engine rotation through a pulley which is driven by the accessory drive belt, a belt driven by a pulley attached to the camshaft, or a sprocket driven by the timing chain to circulate the coolant. The coolant thermostat is a control valve actuated by coolant temperature. When the thermostat is closed, coolant flow bypasses the radiator circuit and returns to the coolant pump. When the thermostat is opened, coolant is allowed to flow through the radiator circuit in order to transfer engine generated heat to the outside air.

The degas bottle, if equipped, holds surplus coolant and removes air from the cooling system, which reduces hot spots. It also allows for coolant expansion and system pressurization, replenishes coolant to the cooling system and serves as the location for service fill.

The cooling fan draws air through the radiator to help cool the system coolant as it passes through the radiator.

The thermostat monitor is a function of the PCM and is designed to verify correct thermostat operation. The monitor will be executed once per drive cycle and has a monitor run duration of 300-800 seconds. If a malfunction occurs, DTC P0125 or P0128 is set, and the malfunction indicator lamp will be illuminated.

For vehicle/engine specific information, see ENGINE COOLING DESCRIPTION AND OPERATION - 2.5L portion of this service information.

See also:
• DTC INDEX - PCM