I’m have a 1992 Olds 98. When the ignition is off I can hear a pump or motor running. After a while it shuts off. I happened to be putting air in my back right tire. I heard air hissing. I’m thinking my tire has a whole in it. I’m feeling around like a retard looking for it. I finally notice that when the motor noise under the hood stops the air sounds at the back tires stops also. I’m afraid if I take it into the shop they are going to think I’m crazy. Does anyone have any idea what this is?
Thanks
It sounds like your car is equipped with air suspension.
The noise up front is the compressor running and the noise in the back is a broken line or air bag leaking.
I believe OK is right and as I recall the fix is not exactly cheap, but you really should have it done.
If the A/C is running just before you shut off the engine, the hissing noise is the freon going from the high pressure side of the system to the low pressure side. The hissing can last up to a minute.
Ed B.
Could be the electric cooling fan … many engine designs run the fan when a hot engine is stopped.
I’m also voting for the air suspension system. Tom&Ray actually had this question on one of their programs and whooped with delight when they figured it out.
Thanks for your advice. At least I have a possible scenario for what’s going on when I try to explain it to our mechanic. If he’s a good one hell have a clue about what I’m talking about. I have a husband who is mechanically challenge so the facilitating the repair will be left up to me.