Top Causes of Car Overheating – And How to Fix Them
Acar overheating can turn any drive into a stressful experience — and in some cases, it can lead to costly engine damage. Whether you’re stuck in traffic in Toronto, driving through the Rockies, or facing a summer heatwave in Vancouver, understanding why your car overheats and how to fix it can help you avoid breakdowns and expensive repairs.
In this blog, we’ll break down the most common causes of car overheating, tips to help you diagnose the issue at home, and when it’s time to call a mechanic.
1. Low or Leaking Coolant
- Why It Happens
Coolant (or antifreeze) plays a crucial role in regulating your engine’s temperature. If there’s not enough coolant due to a leak or neglect, your engine can quickly overheat.
- Signs to Watch For
- Coolant puddles under the car.
- Dashboard low coolant warning.
- Overheating shortly after starting the engine.
- How to Fix It
- Check your coolant level regularly.
- Inspect hoses, the radiator, and the water pump for leaks.
- Top up coolant if needed, but remember — if you’re frequently adding coolant, there’s a leak that needs attention.
2. Faulty Thermostat
- Why It Happens
The thermostat regulates coolant flow based on engine temperature. If it sticks closed, coolant can’t circulate, causing the engine to overheat.
- Signs to Watch For
- Sudden overheating.
- Temperature gauge fluctuating erratically.
- Heater blows cold air even when the engine is hot.
- How to Fix It
- Replacing a thermostat is often an affordable repair.
- For many vehicles, it’s a DIY-friendly fix with basic tools.
3. Water Pump Failure
- Why It Happens
The water pump keeps coolant moving through the engine and radiator. When it fails — often due to a worn bearing or internal impeller damage — coolant flow stops.
- Signs to Watch For
- Coolant leaks near the front of the engine.
- Whining or grinding noises.
- Overheating even with proper coolant levels.
- How to Fix It
- Water pump replacement can be more complex, so this is often a job for a professional mechanic.
- Regular timing belt service (if your pump is belt-driven) helps avoid premature failure.
4. Radiator Issues
- Why It Happens
The radiator’s job is to dissipate heat from coolant before it’s recirculated. A clogged, damaged, or leaking radiator reduces the system’s ability to keep temperatures under control.
- Signs to Watch For
- Visible leaks on the radiator.
- Corrosion or physical damage to radiator fins.
- Coolant discoloration (brown or rusty coolant).
- How to Fix It
- A simple radiator flush can clear internal buildup.
- For physical damage, a radiator replacement is often the only solution.
5. Broken or Non-Functioning Cooling Fan
- Why It Happens
Modern vehicles rely on electric cooling fans to help airflow through the radiator when the car isn’t moving fast enough. If the fan motor, relay, or temperature sensor fails, the fan won’t engage, leading to overheating.
- Signs to Watch For
- Overheating in stop-and-go traffic but not on the highway.
- Fan doesn’t run even when the engine is hot.
- Air conditioning performance decreases.
- How to Fix It
- Check fan fuses and relays first.
- If the fan motor itself is dead, replacement is necessary.
Diagnosing Overheating at Home vs. Visiting a Mechanic
At-Home Diagnosis Tips
- Check coolant level and top up if needed.
- Inspect for visible leaks (hoses, radiator, water pump).
- Listen for unusual noises from the water pump or fan.
- Use an OBD2 scanner to check for cooling system-related error codes.
When to Visit a Mechanic
Overheating persists despite adding coolant.
Visible steam or smoke from under the hood.
Car goes into limp mode.
You’re not comfortable performing DIY cooling system repairs.
Protect Your Car with Quality Cooling System Parts from West Can Auto Parts
When it comes to keeping your car’s cooling system in top shape, quality replacement parts make all the difference. Whether you need premium coolant, replacement hoses, thermostats, radiators, or water pumps, West Can Auto Parts has you covered.
With nine locations across British Columbia and an easy-to-use online store, We help Canadian drivers find the right parts for their vehicles — all at competitive prices.
Shop online or visit us in-store to get expert advice and high-quality parts to keep your engine running cool, no matter the season.
Disclaimer:
This blog is for educational and informational purposes only. For accurate diagnosis and proper vehicle repairs, always consult a certified automotive technician.
