My V6 Camaro (1998) started making strange bubbling sounds suddenly with no changes to the car. It only occurs while accelerating, but not when the gas pedal is pressed while in neutral. The problem is most notable when in first gear. It doesn’t seem to happen in 4th or 5th at all. Also, the one engine temperatures are now in the middle compared to a normally leftward leaning gauge (lower temps).

My first thought was air trapped in the coolant system, but I just bled it out and there wasn’t any change and air did not come out. I’ve got plenty of coolant.

I’m thinking there could be air trapped in the heater core. Any ideas?

 

Boiling as in the coolant is boiling?

If you think the coolant is boiling, then you need to do a pressure test. Cooling will boil at 220 degs with no pressure. As you add pressure the boiling point rises. There are areas around the head that will hit 250 degs. Even if your coolant is at 200 degs there are areas around the combustion chamber that will be much higher then that. Normally in this situation you would still hear boiling after the car shuts off. In most cases it is more noticeable after you shut the car off.



Blown head gasket could sound like boiling as it pushing gases into the coolant system. A coolant pressure test would show coolant pressures rising quickly if the cylinder is being filled with combustion gases.

Many chain style parts stores will let you borrow a coolant pressure tester. Check youtube on how to use it.

Boiling as in the coolant is boiling?

If you think the coolant is boiling, then you need to do a pressure test. Cooling will boil at 220 degs with no pressure. As you add pressure the boiling point rises. There are areas around the head that will hit 250 degs. Even if your coolant is at 200 degs there are areas around the combustion chamber that will be much higher then that. Normally in this situation you would still hear boiling after the car shuts off. In most cases it is more noticeable after you shut the car off.



Blown head gasket could sound like boiling as it pushing gases into the coolant system. A coolant pressure test would show coolant pressures rising quickly if the cylinder is being filled with combustion gases.

Many chain style parts stores will let you borrow a coolant pressure tester. Check youtube on how to use it.

 

It doesn’t sound like boiling, it sounds like bubbling. When accelerating, you can hear water move around some. Edit: it’s actually more like water sloshing around. I’m thinking it’s the heating core because it seemed to be more noticeable with the heat on.

 

can you make a video recording and post on here so we can hear it.

 

This is a video from inside the glove compartment when shifting from gear 1 to gear 2. You can hear the sound slightly, but the engine somewhat drowns it out in the video.

 

is the floor wet under the glove box? wondering if the heater core is failing

 

The floor isn’t wet. I don’t think there is a leak, but it is possible that there is a small, unnoticeable leak. Is there anything recommended to test the heater core? I’d rather not take the car apart just yet.

 

cooling system pressure test like gorn says.