the only way that this can happen is if the airbag its self is leaking just from normal wear and tear. this can also happen if the car has been sitting for a long period of time, the airbag starts to crack and creates a hole, the only problem is the only thing you can do is hear it and cant see it. unfortunately the only thing thing you can do is change the airbag or convert to the spring strut, they usually come with a lifetime guarantee because they will last longer that you and your your kids sometime times. i myself like the air springs but that me. taking them out is a process im not going to lie to you so take the day off just in-case something goes wrong with the removal/installation. make sure that you have the necessary special tools or equivalent if it calls for it and have someone handy just on case the instructions tell you to have someone assist you at a certain point in time. if you need assist. just post it here and hopefully if will get to you or someone else will see it and assist you quickly.
yes
Likely a leak in the system, like one or more of the air shocks are leaking.
Yes
some times you will never . but also they get replaced when they leak or have no bounce control.
Coolant leak.
If you have no leak it is burning oil.
Struts and shocks have a life span of 50k miles.If your struts have started to leak,they need to be changed as soon as possible.
The mechanic needs to see it when it is happening and he can find the leak,./
radiator leak. try adding " leak stop"
The 1997 Pontiac Sun fire axle seal can leak because of age. A bad wheel bearing is the most common cause for an axle seal to leak.
It could, but I wouldn't recommend it in a vehicle that old. It's much easier for 5W to leak out of a vehicle than 10W or 15W.
there is a leak in one of the rear air bags or in the air pump(in front) or the connecting air lines