Q: Overheats and blows cold air when heater is on

asked by on

I could drive about 4 or five miles, temp gauge stays cold then temp rises quickly just pass half way to hot, when I turn heater on to cool down engine it blows cold air. When I park and turn the car off steam comes out from under the hood on passenger side


From what you are describing it would appear to me that you may be having cooling system issues, or are running low on coolant. Low coolant can cause the engine to overheat, and if the level falls low enough can cause heater to blow cold air if no warm coolant is able to find its way into heater core. If there does not appear to be any leaks, I would refill the engine with coolant when it has cooled down and properly bleed the system to see if the problem continues and then go from there. If you want to have this looked at by a professional, a technician from YourMechanic can diagnose your overheating issue and let you know what needs repair.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. Overheats and blows cold air when heater is on

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Car makes popping noise

Hello. The vehicles cruise control system uses an actuator and cable to open the throttle body and hold cruise. The throttle cable and cruise control cable operate independently, but are both linked to the throttle body. Have an experienced technician...

Q: Rattling front passenger side, Chech Engine light 2006 Dodge Ram 1500

Hello - I believe you have 2 different problems: one related to the Check Engine light, and second - something loose in the front suspension which rattles only while the truck is in motion. Check for problem codes - most...

Q: the back passenger floor gets wet nothing else, what is the cause and what to fix?

Hello. Thank you for writing in. The windows have drain tubes and holes that take trapped water from the windows and doors and channels it where it can drain. These drains can become clogged over time with dirt and debris....

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...