Burping the cooling system
Burping the cooling system is the process of removing trapped air from the Pontiac Fiero cooling system after filling, service, or coolant loss.
Because the Fiero has a mid-mounted engine, a front-mounted radiator, and long coolant pipes running underneath the car, trapped air can cause overheating, unstable temperature readings, coolant overflow, or poor coolant circulation.
Overview
Burping is often needed after coolant replacement, hose replacement, radiator service, water pump replacement, thermostat replacement, coolant leaks, or overheating.
The goal is to remove air pockets and ensure that the cooling system remains full after the engine has gone through one or more heat cycles.
Applies to
This article applies generally to all Pontiac Fiero model years.
Details may differ by engine, model year, thermostat housing, radiator cap, thermostat cap, and the condition of the cooling system.
Related topics:
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.
When burping is needed
Burping may be needed after:
- Coolant replacement
- Coolant leaks
- Hose replacement
- Radiator replacement
- Water pump replacement
- Thermostat replacement
- Engine service
- Overheating
- Coolant overflow
- Repeated coolant level changes
Basic burping procedure
A commonly used method is:
- Start with a cool engine.
- Remove the thermostat cap at the engine.
- Remove the thermostat.
- Check the coolant level at the thermostat housing.
- Add coolant if needed.
- Install the thermostat cap without the thermostat installed.
- Start the engine and let it run while monitoring temperature.
- Shut the engine off before it overheats.
- Allow the engine to cool completely.
- Recheck the coolant level at the thermostat housing.
- Add coolant if needed.
- Repeat until the coolant level remains stable after cooling.
- Reinstall the thermostat when the system appears full and stable.
- Check the coolant reservoir level.
Vehicle position
The car may be parked on level ground, but some owners prefer a slight nose-down position, with the front of the car lower than the rear.
A slight nose-down position can help move trapped air toward the thermostat housing, which is one of the highest points in the Fiero cooling system.
Do not use an unsafe or steep slope. The car should remain stable and safely parked.
Signs of trapped air
Possible signs of trapped air include:
- Temperature rises quickly after startup
- Coolant overflows after filling
- Coolant level drops after cooling
- Gurgling sounds
- Unstable temperature gauge readings
- Heater output changes
- Repeated overheating after service
Common mistakes
Common mistakes include:
- Opening the cooling system while hot
- Filling only from the radiator
- Reinstalling the thermostat too early
- Ignoring coolant pipe damage
- Using an incorrect radiator cap
- Assuming the system is full after only one fill
- Not checking the level again after cooling
- Continuing to drive while overheating
If overheating continues
If overheating continues after careful filling and burping, another problem may be present.
Check:
- Coolant pipe damage
- Radiator fan problems
- Thermostat problems
- Water pump failure
- Radiator cap
- Blocked radiator
- Coolant leaks
- Temperature gauge problems
Notes
Burping the system may take more than one heat cycle.
A properly maintained Fiero cooling system should not require constant burping. If air repeatedly returns, check for coolant leaks, cap problems, improper filling, or engine-related problems.