[jso2378]

On my 2010 police impala with the filler cap off there is an occasional small air bubble that comes to the top while idling. When RPM's are increased the water level rises rapidly and overflows. Is this normal or is this a sign of a blown head gasket? Wanted to add that the car runs great. There is no water in the oil or oil in the water. There is no smoke out the exhaust either.

 

[jso2378]

If your head gaskets were blown, it could send pressure into the radiator, the pressure would be too high in your radiator, and your radiator cap should bleed it out to the overflow bottle. This doesn't sound like that. You aren't loosing any coolant, and your oil and water look fine. No system will be 100% completely free of air bubbles, so I wouldn't be concerned by an occasional small bubble. When your RPMs are increased, the water pump speed increases as well. Not sure if you have the cap off at running temp or not, but if you don't, the coolant really doesn't have anywhere to go so there may be more turbulence. Keep an eye on things and you should be fine!

Thanks, The overflow reservoir is right where it should be. I'm sure I am just thinking the worst scenario. It just freaked me out when the coolant rose with the rpm's.