Q: Water from the radiator is going to the expansion tank which then overflows causing engine to overheat.

asked by on

Water from radiator is going into expansion tank which then overflows causing car to overheat. Heaters inside car not working.

My car has 111000 miles.
My car has an automatic transmission.

Hi there. There could be three things that could be causing your engine to overheat and the heater to not work.

  • (1) The thermostat could be stuck shut or causing the cooling system to not flow making the engine overheat and the heater not get any flowing coolant
  • (2) The water pump could have failed or have sludge on it causing the coolant to not cycle making the engine overheat and the heater to not get any flowing coolant.
  • (3) One or both head gaskets could have burned causing the engine to leak coolant into the combustion chamber making the engine overheat and the cooling system to boil over with exhaust gases entering the cooling system.

If you have checked all three areas and you are unable to locate the issue of why the engine is overheating and why the heater is not blowing warm, then I recommend seeking out a professional, such as one from Your Mechanic, to help you diagnose your overheating issue.

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. Water from the radiator is going to the expansion tank which then overflows causing engine to overheat.

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: When I start it up there is a screeching noise

Most commonly, something in the belt drive system will cause this screeching sound. The belt itself may be old. With age, the rubber gets dry, hard, and can form a bit of glazing on the belt surface. That glazing can...

Q: I have a coolant leak somewhere. I think it is from the reservoir because it is coming from that area, but how do I know?

Look around the reservoir, the reservoir cap, and the hoses to the reservoir and see were the leak is coming from. The leak could be a loose hose clamp, cracked hose, or a cracked reservoir. If you need further assistance...

Q: Coolant and noise issue

Generally, when a water pump is going bad, you may hear a bit of a whining sound combined with the pump leaking. The most common place for the water pump to leak from is the pulley shaft seal which is...

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...