Q: Over heating coolant not siphoning back into coolant over flow tank

asked by on

About 2 weeks ago my car started to over heat as i was going on the highway. When i checked my coolant (after i let it cool made it home and let it cool completely) i noticed that the coolant overflow tank was completely empty but the radiator was over filled with coolant. Added more coolant to tank. Couple days later car wad over heating again opened hood and noticed the coolant was spilling out onto the ground because it was being spit outta the overflow port on the cap that goes to the coolant tank. Was told by one mechanic it was my thermostat. Had it replaced yesterday. Today care is still over heating and spitting coolant out of the overflow spout instead of siphoning back into coolant overflow tank.

My car has 250000 miles.
My car has an automatic transmission.

A: It's common for many...

Hey there:

It's common for many mechanics to make the mistake of mis-diagnosing the cause of an overheating situation; especially when they assume it's a thermostat issue. The problem could be caused by a blockage in the coolant tubes running from the radiator to the overflow tank and back to the radiator. However, it also may be due to air trapped in the coolant lines. I think a good idea would be to contact a different ASE certified mechanic, such as one from YourMechanic, and have them complete a coolant flush, which should remove any blockages in the coolant tubes and may solve your problem.

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

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!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: Car cranks, but will not start. If I pull the fuel line off, it starts up to 500 rpm then dies.

Hi there, thanks for writing in. I'd be happy to help. You can disconnect the vacuum line to the fuel pressure regulator on the fuel injector rail to see if fuel comes out of the regulator. If it does, then...

Q: Coolant leaking, engine might be messed up now

You are correct in not wanting to start the car to avoid any further damage. It sounds like you might have coolant leaking into one of the cylinders due to an engine block failure, resulting in a misfire. What needs...

Q: Odd noise when I turn at low speeds.

From what you've described your power steering pump is probably bad. You need to check the oil in it to make sure its not too low, however, I think it's already bad. Once you hear that noise there really isn't...

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
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...