| Re: BMW 5 Series Touring 1997 -
03-31-2008, 08:50 AM
Does it have some sort of pneumatic rear suspension? It could leak air or pressure...Once started, the car senses it and correct it... But BMW does not offer this kind of suspensions on the 5er from what I know.
Does it have the system that makes the rear suspensions harder when you put weight in it? The weight-compensating rear suspension? I know MB usually put it on its station-wagons, but on BMW it's more rare.
On a 1997 BMW it should be an electronic system, so only working when the car has started. I think it could be that, because your car goes up again when it's started, if I understood well?
Maybe it's the problem that the "standard" suspension setting (eg. with the ignition off) is wrong on one side (leaking oil on the suspension arm maybe), so it sinks a bit because it's softer on one side, and when you start it the sensor makes the car even because it senses the problem.
However then, you should have a warning in the dash I think...but not necessarily if the problem is mechanical, on the suspension arm and not on the weight-sensor.
If it has no this system I don't see, a car that sinks is not that uncommon (broken suspension arm, oil-leaking suspension, pressure-leaking pneumatic arm) but a car with metal suspension and sinks when off, but goes up again when started, ???
You should try to see if the suspension arm is not oily, or much more dirty than the others. You also could do the famous test: open the boot, and push the car (hard!) vertically from one side, and then the other side, to see if one side is softer or has more rebound. It's not very reliable but could show a problem if it's very obvious.
It could be the sinking side that is too soft because of a tired suspension, or the other that is too strong because the suspension has no power and does not stop the move of the car. The it will have a lot of rebound, and this side will sit higher.
There a possibilities to test the suspensions of a car, to see if one (or more) are not working good, or if there are differences in one. Not very reliable test, and only shows a dead suspension, but an independant mechanic could do it for less than BMW.
The strange thing is that everything goes back to normal when the car is ignited, which makes me think to this weight-compensation system used on station-wagons. |