P0128

Coolant Thermostat (Below Regulating Temperature)

P0128
Coolant Thermostat (Below Regulating Temperature)
Not urgent
Ranked Possible Causes
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What You'll Notice

Engine takes long to warm up, Poor heater performance in winter, Reduced fuel economy, Temp gauge reads lower than normal

Cost Estimate
JobRange
Thermostat replacement (DIY)$20–$60
Thermostat replacement (shop)$120–$300
Coolant temp sensor replacement$30–$120
Parts You Might Need
• Thermostat + housing gasket
• Coolant temperature sensor
• Coolant (top-off)

These percentages are general patterns, not a diagnosis for your specific vehicle. Have a technician scan your car to confirm which component is actually failing.

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