Model S / X Air Suspension Sagging Overnight
Model SModel X
Your Model S or Model X is sitting low in the driveway this morning, one corner sagged to the bump stops. Before you panic-buy a compressor or air spring, there's a fast way to tell which one actually failed — and it's not the obvious one.
The symptom
The classic tells: - One corner or one side sits noticeably lower after sitting a few hours or overnight - The whole car drops to "very low" or "entry" when parked but the compressor runs constantly - A bumpy ride or clunk over the front end on a specific corner - Occasional "Suspension — vehicle is lowering" on the touchscreen
The two suspects
1. Leaking air spring (the common one). Over years, the rubber bellows on an air spring develop micro-cracks — usually at the fold lines near the top or bottom — and bleed air slowly. This is why the car sags overnight and pumps back up when you drive.
2. Failing compressor (less common, misdiagnosed). The compressor builds and holds air, and its job is to maintain ride height. If one corner is down but the compressor runs fine and the car levels back up, it's almost never the compressor.
How to confirm in 5 minutes
Soap test the bellows
Mix a squirt of dish soap with water in a spray bottle, jack up the corner that's sagging, and spray the full length of the air spring bellows. Watch for a steady trail of bubbles. If you see growing bubbles, that spring is leaking — confirmed.
The critical test: is it level after a drive?
Here's the trap — if the corner still won't hold the car level even right after driving (not just overnight), and the compressor runs continuously trying to catch up, then suspect the compressor or a leak in the air lines or valve block. But a car that sags when parked and pumps right back up is textbook leaky spring.
The rule: sagging at rest = air spring. Continuous compressor run trying to maintain height = compressor, line, or valve block.
The fix
Confirm the leaking corner with the soap test, then it's a spring replacement — one corner at a time is fine; you don't typically chase all four unless they're all old. Jack the car, support it, deflate the bad spring, and swap it.
Shop tip: always replace the spring on the opposite corner the same side — the left/right springs wear together. And check the compressor's dryer — a failing dryer is what kills compressors prematurely.
FAQ
Is it safe to drive with a sagging corner? Short distances, low speed, yes — but the ride is bad and it's only getting worse. Get it fixed soon.
Can I fix just the one spring? Yes. Replacing the single failed corner is standard practice unless the others are old.
Are aftermarket air springs OK? Many independent techs fit quality aftermarket springs at a fraction of OEM cost — confirm the kit is for your exact model and year.