BMW X5 Rear Suspension Drops Overnight - How to Fix This?

The rear air suspension in your BMW X5 can drop overnight because of rear air bags problems, an air leak in the system, valve block issues, or damaged air lines. It's not that hard to damage something like a plastic thread on one of the lines or the compressor that pumps up the air in the air springs.

Air suspension problems highlights

• Level of importance:medium
• Common reasons:internal suspension failure, electronic problem
• DIY inspection:impossible
• DIY repair:impossible
• Average price in shops:$550 - $1,900
• Average time:5 - 20 hours
• If ignored:fatal failure, car drops, hard driving

Symptoms and consequences of rear suspension dropping in the X5

So, I want to make sure that we are on the same page. I'm talking today about the problem when your X5 with air suspension suddenly drops overnight. Then it may hold the air for some time and then drop again. Or it can drop every night or every time you leave the vehicle for more than 5 hours, for example.

The problem is not that pleasant and here's what you get:

• the rear suspension is in its lowest position every morning or occasionally;
• you need to wait till the compressor pumps up the suspension when you start the car;
• sometimes, you may notice that the suspension is not going back to normal and you have to drive like that;
• also, there may be some error messages and warning lights on the dash of your X5.

You better register all the symptoms before you go to the dealership or to the trusted repair shop. The more you know about the problem, the less time the mechanic will need to diagnose the vehicle.

So, if the symptoms in your vehicle resemble the situations that I described above, you should read this article and see what exactly can lead to this. In most cases, though, you will need some professional help for proper diagnosis.

What exactly can cause rear suspension sagging in the X5?

Air suspension may drop because of several factors. It's not always the mechanical failure, sometimes it may be caused by electronic control units because everything in your X5 is powered by electronics. That's why you aren't protected from possible glitches.

But still, when it comes to air suspension in a BMW car, in most cases, the problem should be searched exactly in one of the parts that form this type of suspension.

Here are the possible reasons:

1. The air springs are bad

If only one of the sides is dropping, chances are that the problem is in the air spring or airbag. This is the main part of the suspension that substitutes the metal spring and offers you great soft driving.

Also, the spring serves as the part that can raise or lower the vehicle. And if it fails and the pressure isn't building up in the spring, it can drop. Sometimes, you can repair the spring, but, in most cases, you will need to replace it with a new one.

2. Valve blocks

Each spring is controlled by a series of valves. Each valve and valve block can go bad and start leaking. It means that the spring will lose air and will gradually sag. This may happen quickly - just for several minutes - if the leak is bad. But most often, this may take about 5-8 hours. During one night, the suspension will drop.

Then, you will start the engine, the control unit will see that the suspension is too low, and the compressor will pump up the pressure in the spring. But after you turn the engine off, the spring will start losing air again.

3. Air lines

There are several lines that are connected to each spring and they all may leak. Road debris, careless suspension repair, driving on high road curbs, and some other factors can kill one of the air lines.

When a certain air line start leaking, you will obviously feel that the car is dropping once you stop the engine. But if the leak is just tiny, the car may drop quite slowly and this will only be noticeable when you leave the X5 for a long time. Anyway, this requires an immediate reaction.

4. The compressor

Air suspension is powered by the compressor that builds up air pressure in each cylinder. It has valves in it and those valves can also leak some air. I would say that the compressor is the second most common reason for your rear suspension sagging in the BMW X5 after the valve block. I've seen situations when these two units were malfunctioning at the same time and this made the diagnosing process pretty tough.

Just remember that if you replaced the compressor and the car keeps sagging, it may mean that not only the compressor but also the valve block or some other part needs replacement. It doesn't automatically mean that the compressor was OK.

5. The control units

Your X5 rear air suspension is controlled by special units that rely on the readings of certain sensors. It means that if the control unit or one of the sensors fails, you will most likely not get the proper work of this suspension.

You may try to reset the control blocks using a scanner or disconnect the battery for 10 minutes. But I haven't seen any cases when this helped.

Also, you may use the scanner to check the control unit and its suspension settings. Sometimes, just by looking at the readings of some sensors, you may identify the problem.

How to solve the problem of the sagging X5 rear suspension?

Well, solving this issue is not that easy. You will obviously need to replace some parts but finding which part is malfunctioning is pretty hard. Sometimes, people also have problems with the quality of aftermarket parts and only some X5 owners buy OEM parts for air suspension because they usually cost a fortune.

This doesn't mean that there are no possible ways to solve the problem. Here's what you can do:

• Find the malfunctioning part

First of all, you need to understand which part is faulty. You can use soapy water and cover the valve blocks and air line connections with it to see if it leaks air. You may use the scanner and look at the readings of all connected sensors. You may also take some cheap used parts and install them to see if something changes. But you need to find the exact problem that tortures your vehicle.

• Buy the new aftermarket part

Unless you are ready to pay a huge price for the new OEM part for the air suspension, you may buy some aftermarket alternatives. But be careful - buy the parts that are covered by warranty. If they fail, you can get a refund.

• Have the new parts installed by professionals

Unfortunately, the air suspension is not a unit that you can repair or rebuild in your garage with your own hands. This requires some expertise and experience. Of course, if you are a BMW mechanic yourself, you can use your experience and avoid paying money to dealerships or repair shops. But not many of us have this precious background.

• Replace the air suspension with the spring kit

If your X5 already has more than 150,000 miles on it, the air suspension is going to be pretty expensive to maintain. The main problem is that the OEM parts are highly expensive and all aftermarket parts are not long-lasting.

If you are tired of investing money in air suspension in your BMW SUV, you may try getting a metal spring kit and replacing the air springs with traditional metal springs. This will cost you some money, especially in terms of labor, but this will solve all your problems with air suspension like sagging or uneven positioning.

Can you drive with a dropped rear suspension in the X5?

It's not prohibited to drive with the rear suspension sagging in your BMW X5. But you may badly hurt the struts and kill the air suspension to make things even worse. So, the worst thing you can do is just keep driving as you usually drive. Of course, you don't need to call a tow truck if this happened with your car.

Even if the compressor can't level the vehicle after you start it, you may carefully and slowly drive to the dealership or to the trusted repair shop.

But if you keep driving, your compressor will go crazy because of the amount of work it will have to do and it will most likely die quite soon. So, I wouldn't recommend driving your X5 for a long time and ignoring the problem of the dropping rear suspension.