I drive a chevy cruiz, and my coolant is bubbling/boiling like. There is no leaks, nor overflows, my coolant doesn't drain, and my vehicle doesn't overheat either. According to my temp gauge. Heck, my fan doesn't even turn on! I don't know if that could have something to do with it or not. What could cause this?

  • 2
    A common reason is a cracked cylinder head gasket blowing exhaust gas into the cooling system. Get it fixed before it turns into a bigger problem (e.g a bigger gas leak pumps the coolant onto the road while you are driving, the temperature gauge shows nothing because it isn't in the coolant any more, and the engine seizes up...)
    – alephzero
    Jul 7, 2021 at 13:41
  • I've only had this happen once and it was a cracked block, but any combustion gas leak into the cooling system can cause this. Not sure if there are other explanations for it. You can get coolant testing kits (I believe Autozone loans them) that will sniff for combustion gas in your coolant, then you will know for sure. Jul 7, 2021 at 15:49

1 Answer 1


If you recently changed your coolant it might be trapped air inside the system getting out. But most likely is compression going into cooling system due to blown gasket or cracked block/cylinder. This will become a problem in the future, try to fix it as soon as possible.

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