Coolant filling procedure
Coolant filling procedure is the procedure used to refill and bleed the Pontiac Fiero cooling system.
Because the Fiero has a mid-mounted engine, a front-mounted radiator, and long coolant pipes running underneath the car, the cooling system must be filled carefully to avoid trapped air.
Overview
The Fiero cooling system is different from many front-engine cars. The radiator is at the front of the car, while the engine and thermostat housing are at the rear.
If the system is filled incorrectly, air can remain trapped in the cooling system. This can cause overheating, unstable temperature readings, coolant overflow, poor circulation, or repeated coolant loss.
Applies to
This article applies generally to all Pontiac Fiero model years, but details may differ by engine, model year, thermostat housing, radiator cap, and cooling-system condition.
Related topics:
- 1984 Pontiac Fiero
- 1985 Pontiac Fiero
- 1986 Pontiac Fiero
- 1987 Pontiac Fiero
- 1988 Pontiac Fiero
- 2.5L Iron Duke
- 2.8L V6
Safety
Only open the cooling system when the engine is cool.
Hot coolant is pressurized and can cause serious burns. If the engine has overheated, allow it to cool before removing the radiator cap, thermostat cap, or any cooling-system part.
Before filling
Before filling the system, inspect:
- Coolant pipes under the car
- Radiator condition
- Radiator cap
- Thermostat cap
- Hoses and clamps
- Water pump
- Thermostat
- Coolant reservoir
- Visible leaks
Damaged or crushed coolant pipes can restrict flow and cause overheating.
Related topics:
Basic filling procedure
A commonly used Fiero filling method is:
- Make sure the engine is cool.
- Park the car on level ground.
- Remove the thermostat cap at the engine.
- Remove the thermostat.
- Remove the radiator cap.
- Slowly fill coolant at the thermostat housing until coolant reaches the radiator.
- Install the radiator cap when coolant is present at the radiator.
- Continue filling at the thermostat housing until the system is full.
- Leave the thermostat out temporarily.
- Install the thermostat cap.
- Start the engine and allow it to warm up while watching temperature and coolant behavior.
- Shut the engine off and allow it to cool.
- Recheck coolant level at the thermostat housing.
- Reinstall the thermostat once air has been removed and the system level remains stable.
- Check the coolant reservoir level.
Burping the system
Burping the cooling system means removing trapped air from the system after filling.
Air may need to be removed over several heat cycles. After the engine cools, the coolant level should be checked again.
Related topics:
Common mistakes
Common mistakes include:
- Filling only from the radiator
- Leaving air trapped in the system
- Installing the thermostat before the system is full
- Using the wrong radiator cap
- Ignoring crushed coolant pipes
- Assuming overheating is caused by the thermostat without checking for air
- Opening the system while hot
- Overlooking leaks
Symptoms of trapped air
Symptoms of trapped air may include:
- Temperature gauge rises quickly
- Coolant overflows
- Heater performance changes
- Radiator fan operation seems normal but temperature still rises
- Coolant level drops after cooling
- Gurgling sounds
- Repeated overheating after refill
Diagnosis if overheating continues
If the car still overheats after proper filling, check:
- Coolant pipe damage
- Radiator fan problems
- Thermostat problems
- Water pump failure
- Radiator cap
- Blocked radiator
- Temperature gauge problems
- Coolant leaks
Notes
A properly maintained Fiero cooling system should not overheat.
Repeated overheating after filling usually indicates trapped air, coolant loss, restricted flow, fan problems, cap problems, water pump problems, or another cooling-system fault that needs diagnosis.