Overheating
Overheating is a common cooling-system complaint on the Pontiac Fiero.
Because the Fiero has a mid-mounted engine, a front-mounted radiator, and long coolant pipes running underneath the car, overheating diagnosis should include both normal cooling-system checks and Fiero-specific issues such as trapped air and damaged coolant pipes.
Overview
A properly maintained Fiero cooling system should not overheat. When overheating occurs, common causes include low coolant level, trapped air, damaged coolant pipes, thermostat problems, radiator cap problems, water pump failure, radiator fan problems, blocked radiator flow, coolant leaks, or incorrect filling procedure.
Overheating should be diagnosed carefully before replacing parts.
Common causes
- Air in cooling system
- Low coolant
- Coolant leaks
- Coolant pipe damage
- Thermostat problems
- Radiator cap
- Water pump failure
- Radiator fan problems
- Blocked radiator
- Temperature gauge problems
Coolant filling and trapped air
Trapped air is a common cause of Fiero cooling problems. Because the radiator is at the front of the car and the engine is at the rear, the system must be filled and bled correctly.
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Coolant pipes
The Fiero uses long coolant pipes under the car. These pipes can be crushed or damaged by incorrect lifting, jacking, or previous repairs.
Damaged coolant pipes may restrict flow and cause overheating.
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Radiator fan operation
The radiator fan must operate correctly to control temperature, especially at low speed, in traffic, or when the air conditioning is used.
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Thermostat and caps
Thermostat problems, incorrect caps, weak caps, or leaking caps can affect coolant flow and system pressure.
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Water pump
A failing or incorrect water pump can cause poor coolant circulation. Some replacement pumps use plastic impellers, and impeller condition should be considered during diagnosis.
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Diagnosis
A practical diagnostic order is:
- Check coolant level when the engine is cold.
- Inspect for visible leaks.
- Verify the system was filled correctly.
- Check for trapped air.
- Inspect the coolant pipes under the car.
- Check radiator fan operation.
- Check thermostat operation.
- Check radiator and thermostat caps.
- Inspect hoses and clamps.
- Check water pump condition.
- Verify temperature gauge accuracy.
- Check for combustion gases in the cooling system if other causes are not found.
Warning signs
Stop driving and investigate if the temperature rises rapidly, coolant overflows, steam appears, the warning light comes on, or the engine begins to run poorly.
Severe overheating can damage the engine.