why is overflow tank boiling on car
If so, you should have gotten it in to the mechanic asap. With the coolant disappearing and the oil being sludgy, I suspect a head gasket leak. The boiling in the overflow tank may be air escaping from the radiator due to pressure from the leak.Have the engine pressure-tested. A bad gasket can cause serious damage if water dilutes the oil. have a 2011 Chevrolet Aveo and for the last couple of months the antifreeze has been disappearing out of my overflow tank...and NOW for the last couple of weeks the coolant has been boiling and the car overheats badly...and I&#39;ve recently gotten an oil change in December but now my oil in my...