Heater Not Working
No heat is usually low coolant, a thermostat stuck open, a clogged heater core or a blend door fault.
Can I drive it? Drive with care
Safe to drive, but check the coolant level and temperature gauge. Low coolant also risks overheating.
Typical repair cost
$20-$60 for coolant, $100-$250 for a thermostat, $600-$1,300 for a heater core.
General US estimates, not quotes. Prices vary by region, vehicle and shop.
Symptoms to Look For
These signs indicate you might be experiencing this issue
- Blowing cold air only
- Engine temperature normal but no heat
- Sweet smell in cabin (Coolant leak)
- Heater controls feel stiff or unresponsive
Potential Causes
Most likely reasons for this problem, sorted by probability
Repair Solutions
Step-by-step instructions to diagnose and fix the problem
1Check Coolant Level
- 1
Ensure engine is cold
- 2
Check radiator and overflow tank levels
- 3
Low coolant prevents hot water from reaching the heater core
- 4
Top up with correct coolant mixture if needed
Need professional help?
Find a repair shop near you, or describe your exact symptoms to the AI mechanic
When to See a Mechanic
Do not wait if any of these apply
- Coolant level keeps dropping
- A sweet smell or fogged windows
- The gauge stays low or the engine overheats
How to Prevent It
Simple habits that stop this problem coming back
- Flush coolant on schedule
- Check the coolant level monthly
- Fix coolant leaks early
Frequently Asked Questions
Why is my heater blowing cold air?
Low coolant or a thermostat stuck open are the usual causes. A blend door fault is also possible.
Can a heater problem cause overheating?
The same causes, low coolant or an air pocket, can. Watch the temperature gauge.
Related Trouble Codes
Codes a scan tool may show with this problem
Related Issues
AI-generated and informational only. This is not a diagnosis of your specific vehicle and does not replace inspection by a qualified technician.