Skip the auto shop - Our mechanics make house calls

Q: My radiator is full and my overfill is full yet my car still is overheating.

asked by on

My radiator is full and my overfill is full yet my car still is over heating. I just had a new radiator and thermostat put in. Why is it still overheating?

My car has 178000 miles.
My car has an automatic transmission.

Hi there. First check the reservoir cap and make sure that it can hold the pressure that it says on it. If the cap can hold the pressure, then either the water pump is not working or the engine has a blown head gasket. To check the head gasket, get a block tester from a local parts store and put it together with the blue chemical in it. Remove the radiator / reservoir cap and start the engine. When the water is getting warm, there will be steam coming out of the neck. Take the block tester and use it to suck up the steam vapors only. If the blue fluid turns green or yellow, then combustion gasses are getting into the cooling system. This would indicate a blown head gasket, cracked cylinder head, or a cracked block. If you need further assistance with your engine overheating, then seek out a professional, such as one from Your Mechanic, to help you.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 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
  • Home
  • Questions
  • My radiator is full and my overfill is full yet my car still is overheating.

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: Driving from Washington to Oregon when I got home battery boiled over. The 4 wheel drive dash lights and overdrive are on.

Hello. With so many lights indicating on the dashboard such as the check engine light and the overdrive light they will certainly be codes present inside of the transmission control module and engine control module. I suggest that a technician...

Q: car overheating

If the reservoir is cracked you should replace the reservoir and cap. Once that is done, have the coolant changed. Use a 50/50 mixture of coolant and water. If you need help with this repair, consider YourMechanic, as a certified...

Q: For some reason I am getting diesel fuel in my coolant to the point it makes it overflow.

Hi there. The engine that you go has a blown head gasket. The fuel is leaking from the combustion chamber to the cooling system and causing the diesel to get into the cooling system and make the coolant bubble out...

Related articles

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...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.