I have a 2018 Suburban LT with the auto ride leaving system.

The behavior of the system has changed, from it being pretty much unknown to me to having an air pump running much of the time.

It seems the ride leveling system has a leak that causes the pump to run regularly when there is a load in the rear of the vehicle (such as having people sitting in the rear seats).

With the whole family (5 persons) in the vehicle, the pump turns on regularly, and is running most of the time—approximately 75% of the time. It runs for a few minutes, turns off for about a minute, and repeats continuously. And the pump is fairly loud, and quite noticeable even inside the vehicle with the windows rolled up.

I have taken the vehicle to my dealer twice now, and was told the first time it might be failing but until it fails GM won't do anything until it completely fails with an error code on the instrument panel. The second time, I was told it is behaving normally.

I decided to document just how often the pump runs and am wondering what you all think.

Note: all measurements are made on relatively level land with the vehicle on and stationary. All the heights are measured from the road to the inner bottom of the trailer hitch.

The nominal ride height with no load is 53.0 cm: With no weight in the rear, the ride leveling system held the rear of the vehicle at 53.0 cm. The ride leveling system initially filled the system briefly (about 2 seconds) and didn’t require further filling. This is likely because the suspension/shocks hold the vehicle at this height. This is consistent with the intent of the system to maintain the same ride height as the unladen vehicle.

With a load of 270 lbs added in the rear of the vehicle, the level immediately dropped to 51.0 cm and the pump kicked on. After about 53 seconds of the pump running, the ride level reached 52.5 cm. Over a period of about 90 seconds, the height gradually dropped to 51.3 cm and then the pump kicked on again. This cycle repeats indefinitely. Based on the data collected below, the pump will run approximately 33% of the time.

The data collected:

Run Height(cm) Fill(s) Leak(s)
1 51.0 - 52.5 53 90
2 51.3 - 52.5 46 92
3 51.0 - 52.3 42 94
4 50.8 - 52.3 42 92

With a load of 550 lbs added in the rear of the vehicle, the level immediately dropped to 49.0 cm and the pump kicked on. After 120 seconds of the pump running, the level reached 50.7 cm. Over a period of only 50 seconds, the ride level dropped steadily to 48.8 cm and then the pump kicked on again. This cycle repeats indefinitely. Based on the data collected below the pump will run approximately 72% of the time. This is most representative of my family riding in the vehicle.

The data collected:

Run Height(cm) Fill(s) Leak(s)
1 49.0 - 50.7 120 50
2 48.8 - 50.7 113 52
3 48.8 - 50.8 175 53

Thoughts?

 

I think you've put more effort into this than you should ever have to. Go back to the dealer. it's under warranty. Don't leave until it's fixed.

 

Its got a leak. The dealer doesn't want to tie up a service bay with your truck and, a guy with a soapy-spray bottle hunting for line-leaks.

 

I agree...this is much more effort than I would have believed necessary. I find it difficult to believe that the dealer couldn't / wouldn't fix it.

 

I can't speak to whether the service bays would be tied up or not, but they had the vehicle twice for about a day each time. It may have never seen a bay so you might be right.

 

Thanks for the thoughts.

Since the dealership we purchased the vehicle from couldn't/wouldn't fix it after two times, I'm taking it to another local dealer. Luckily I live in the SoCal area where there are numerous dealerships. The shop that maintains my EROD El Camino has connections there and is willing to make sure the right eyes see it. Appt for Friday morning.

 

It occurred to me to ask you if you have had the vehicle off the wheels, for say, a tire rotation? Or even an over-head oil change, where the wheels have been free to drop? That was something that would cause Lincoln / Mercury air-ride suspensions to over pressurize. I never learned much about them, except there was a switch in the trunk that got missed many times and replacement coil-over shock McPherson struts that would replace the entire mess, which usually ended up with a burned out motor too.
Much cheaper than repairing what was installed.

You might run your VIN at vehiclehistory.com and see if there is a recall on the vehicle.

 

vandeneykel
As well researched and evidenced your problem has been documented, I am sure the following advice will be looked at very carefully by you between now and tomorrow at the dealership, there in SoCal.

I just looked at the fact that you have serviced this vehicle twice for the same issue.
This will be a new dealership.
It is still a GM dealership, so don't let that throw you.
This will be their third swing at this problem.
Their records back up yours.
You want out of the car?

ASSERT AND INVOKE YOUR BUY-BACK RIGHTS TOMORROW AT SERVICE-TIME CHECK-IN. THEY WILL HAVE ALL DAY TO FIX IT, AND IF THEY DON'T, THEY HAVE TO BUY IT BACK FROM YOU.
GOOD OLD LEMON LAW
RIGHT THERE IN CALIFORNIA.

DON'T FORGET TO BRING YOUR TITLE TO TRANSFER ACROSS FOR THOUSANDS OF DOLLARS.

DON'T FORGET TO TAKE LOTS OF PICTURES OF EVERYBODY FOR YOUR RECORDS. YOU CAN ALWAYS DESTROY THEM LATER.

YOU MIGHT ALSO WANT TO TIP OFF THE NEWS.
GIVE THEM ALL KINDS OF PUBLICITY.

/s

 

Even if the vehicle goes out of warranty, you've documented the issue during the warranty period, and dealerships need to honor.

We bought a 2005 Yukon XL in 2010 and that leveling system has never worked.

 

I took the vehicle to a different dealer and they found one of the rear shocks has a leak. They ordered the parts and will install Monday. Hopefully this will be it. Makes sense, though.