New to the forum - question about rear noise when I turn the car off

Hello everyone

I bought a 95 last year and absolutely love it. My question is, when I turn the car off, I hear a motor type sound coming from the rear of the car, almost like an unwinding of a motor. What is it?

Hi
I bought my 95 in Nov. last year.
I always hear my power antena motor go down when I shut my car off.

I remember that sound. It's the self-leveling rear suspension, and what you think you hear is exactly what it is; an air pump motor.

Ilan is correct, that noise is normal and is coming from the rear self leveling suspension. It actually runs quite often but with the car running you might not be able to hear it. It will run for a couple seconds after you shut it off if you're parking on uneven ground. I'd only be concerned if its running for almost 5 mins after shutting down when the ground appears to be level as that could indicate a leak in the shocks or lines or a mis adjusted height sensor.

Ummmm, the air pump should only run when you start the car, or when you put something heavy in the trunk. If that pump is running while you're driving, or when you shut the car off, you have an air leak somewhere. A normally functioning system hardly ever operates.......

Or, like someone has already mentioned, your Antenna is going down.

I agree with that under ideal conditions, but if you park on uneven ground with the ass end slightly elevated like I do then it attempts to level whenever I park. Depending on how high the back is when I stop sometime my weigh of getting out of the car is enough to even it out.

One solution is to have someone else turn off the car and listen for where the sound is coming from. The antenna is in the rear passenger side fender behind a panel in the trunk, whereas the airpump is mounted under the car near to the rear passenger side tire. First figure out which it is and then you'll know for sure if you need to look any farther.

Abaddon wrote:

Ummmm, the air pump should only run when you start the car, or when you put something heavy in the trunk. If that pump is running while you're driving, or when you shut the car off, you have an air leak somewhere. A normally functioning system hardly ever operates.......

Or, like someone has already mentioned, your Antenna is going down.

Agreed, the body computer is set to let air *out* of the rear struts when parked in order to extend the life of the struts. It's not at all like the Ford system, which inflates the air springs when car is parked for an hour to 90 minutes so it's sitting at city height when parked. In the Buick (GM) system the car has coil springs and the shocks have bladders for a load leveling assist via air. When the Ford system quits the car is barely drivable. When the GM system quits it is drivable but it only takes a driver more than #150 to make it saggy.

I am not saying you have a leak or a problem.

I am agreeing in the recommendation to have someone else drive the car a mile and park it in front of you and turn it off so you can determine if this is air pump noise or power antenna noise. Your power antenna original? Working? Do tell.

PS: to the rest of you. If the air ride system does more than let the air out after you park, you should consult your service manual to figure out if that's normal.

Compressor... no question about it. I own a 95 its compressor goes off and on fairly often (running or not) when parked, even before I put the stereo system in. System has no leaks and functions 100%, typical operation noise for that car. I wouldn't worry bout it. The antenna (sounds like cordless screwdriver) and compressor (sounds like a portable camping air compressor) are easlily distinguishable from one another they sound worlds apart.

I've heard many ppl say that the air pump isn't supposed to come on if the car is off, but remember we are talking about the odd-ball 95 so maybe its different. I know my car will come on if I park on uneven ground or even stop at a long light that's on a hill. I'm gonna have to check my service manual when I get home (if its in the 1 I have) to figure this out for certain. Its possible that gm redesigned the 96-up models to only exhaust due to drained battery complaints from 95 owners. I know when my shock was busted it would run until it timed out every time I shut off the car so it definitely will run when off.

Derek wrote:

I've heard many ppl say that the air pump isn't supposed to come on if the car is off, but remember we are talking about the odd-ball 95 so maybe its different. I know my car will come on if I park on uneven ground or even stop at a long light that's on a hill. I'm gonna have to check my service manual when I get home (if its in the 1 I have) to figure this out for certain. Its possible that gm redesigned the 96-up models to only exhaust due to drained battery complaints from 95 owners. I know when my shock was busted it would run until it timed out every time I shut off the car so it definitely will run when off.

The drained battery theory wouldn't surprise me , i run a CTEK charger on mine all winter while it sits, with it on the "SUPPLY" setting. Helps to prevent the compressor and other constant power systems from killing the battery while it sits.

Derek wrote:

I've heard many ppl say that the air pump isn't supposed to come on if the car is off, but remember we are talking about the odd-ball 95 so maybe its different...

FWIW, my '97 compressor has never come on with the key off, and my 1981 Eldorado with the original implementation of this same system never ran with the key off either... they only exhaust.

I vote antenna. In my car it goes back down when I open the door. Otherwise the stereo will keep running for a certain amount of time while the car is off.

DEMonte1997 wrote:

I vote antenna. In my car it goes back down when I open the door. Otherwise the stereo will keep running for a certain amount of time while the car is off.

If you have the radio on when you turn the car off, the antenna motor will always turn on and draw the antenna down. The air ride compressor usually comes on after start up and randomly there after if there is a leak in the system.

Derek wrote:

I've heard many ppl say that the air pump isn't supposed to come on if the car is off, but remember we are talking about the odd-ball 95 so maybe its different. I know my car will come on if I park on uneven ground or even stop at a long light that's on a hill. I'm gonna have to check my service manual when I get home (if its in the 1 I have) to figure this out for certain. Its possible that gm redesigned the 96-up models to only exhaust due to drained battery complaints from 95 owners. I know when my shock was busted it would run until it timed out every time I shut off the car so it definitely will run when off.

Right.

I don't own a '95 and I am not gonna pretend to know it all, but I am gonna encourage reading the fine manual. Hopefully someone will do so and repost.

Ok when I'm wrong I'll admit it. To all 95 owners the good book says; 'The compressor is activated when the ignition is on and weight is added to the vehicle. The exhaust solenoid is connected directly to battery positive, enabling the system to exhaust with the ignition off when excess weight is removed.' Hmmm I guess its time to check for leaks again... But then why would it come on at all if the book says that it can't?

A. Somebody had fu*%ed with it...

B. It's something else. (Have you actually eliminated the antenna as the source of the noise?)

I wouldn't say your wrong, I for 1, misunderstood what you were asking regarding the ignition. I was under the impression you were asking if the compressor works without the engine running (ignition on) which it does. The key must be in either the ignition or acc position in order for the compressor to kick in. constant power systems must only be the security system, and the clock. Either way nothing to panic over, I have had this issue as long as I have owned my 95 Riv and haven't had an ounce of trouble with it. And trust me I am pretty anal about my cars (in particular the Riv), if they cause trouble they get repaired quickly. When I did my amp swap last month I had the key set to ACC and was in and out the trunk all day, the compressor kept going off and on with every trip in/out, which IMO would be normal with a 300lbs. stereo and a full grown man in and out of the trunk.

In the meantime post some pics of your whip if you haven't already done so. Here we all love our Rivporn!

Mine was a '95. It's the air ride compressor, and it sounds like one. Doesn't sound anything like the small antenna motor.

Wow, thanks for all the responses. I normally hear it when I get home and am parked on a downward slope, so it sounds like it's normal for the car. Thanks again, I really appreciate it.