Symptom Guide
Engine Overheating
Gauge climbing into the red? Pull over safely. Here's what's wrong and what to check.
What's happening
How urgent is it? High — deal with this soon
Most likely causes
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1
Low coolant from a leak
The number one cause. Check the overflow tank and look for puddles.
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2
Stuck-closed thermostat
Traps coolant in the engine. Overheats within 10-15 minutes of driving.
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3
Failed cooling fan
Overheats in traffic but cools on the highway; the fan isn't pulling air.
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4
Bad water pump
No circulation. Often leaks or squeals before it fails completely.
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5
Clogged radiator
External debris or internal corrosion blocks heat transfer.
How to diagnose it — in order
-
1
Pull over safely and shut the engine off. Never open a hot radiator cap.
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2
Once cool, check the coolant level in the overflow tank.
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3
Look under the car for green, orange, or pink puddles.
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4
Check if the cooling fan spins when the AC is on max.
Trouble codes tied to this symptom
If your scanner shows one of these, read its dedicated trouble-code page for the full diagnosis.
Repair guides for this symptom
Repair guide
2018-2024 Chevrolet Equinox - Thermostat Replacement
Step-by-step DIY for this repair.
Repair guide
2015-2020 Chevrolet Tahoe - Thermostat Replacement
Step-by-step DIY for this repair.
Repair guide
2010-2024 Toyota 4Runner - Thermostat Replacement
Step-by-step DIY for this repair.
Repair guide
2015-2019 Ford Explorer - Thermostat Replacement
Step-by-step DIY for this repair.
Related symptoms
General diagnostic information, not a factory service procedure. If you're unsure, have a qualified technician confirm the diagnosis before buying parts.