Q: My car is spitting coolant from the overflow tank

asked by on

2004 Chevy Tracker started spitting coolant from the overflow tank. No overheating problems or leaks beforehand until now.

Without any warning, most of the coolant had blown out of the overflow tank. After allowing it to cool for a couple of hours, I refilled the radiator and overflow tank to recommended levels. Drove it another ~6 miles and it started overheating again. Opened the hood and found the overflow tank FULL and spitting coolant again.

The system appears leak free but obviously something ain't right given the symptoms. The coolant system was replaced four years ago after a collision with a deer and everything has worked perfectly since then. This just started today for no apparent reason. What's up with that?

My car has 160000 miles.

Hi and thanks for contacting YourMechanic. Check the coolant strength to see what the protection is. A good protection will read 164 degrees Fahrenheit. Check the radiator cap to see if the seal is torn or if the release valve inside the cap has failed or is sticking open. A radiator cap can cause the system to boil and spit out all of the coolant.

If you have good coolant and the radiator cap is new, then the thermostat could be sticking causing your coolant to heat up too much which in turn causes the system to boil. To check if the thermostat is working, start up the vehicle when it is cold and watch the coolant temperature gauge. When the thermostat opens, the gauge will drop a little.

If the gauge does not show this, then, when the upper radiator hose gets hot, right after the thermostat opens, the coolant flows through the hose and you would be able to feel this. Plus, the hose will begin to get cooler as the coolant travels through the hose. If the thermostat was replaced and you still have a boiling issue, then the head gasket has burned on the engine.

If you need assistance, then seek out a professional mechanic, such as one from YourMechanic, to help determine why the car is overheating and why the coolant is boiling out.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. My car is spitting coolant from the overflow tank

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: Light brown sludge in radiator and no coolant

The radiator having no coolant and oil in the coolant with the smoking out the exhaust is an indication you may have blown a head gasket or possibly the heater core broke and lost coolant then overheated the engine. Check...

Q: Q: Fuel pump not getting power

The only quick fix I can think of is to check the inertia switch on the left side of your truck. It is a switched designed to shut off the fuel pump in the event of a crash. As they...

Q: I replaced my fuel pump on my 04 suburban but it still will not crank. Could this mean my new fuel pump is bad?

A bad fuel pump is only one of many reasons why a truck might not start. The way to test a fuel pump is to put a pressure gauge on the fuel rail and measure the fuel pressure and volume....

Related articles

Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...