jmdav89

I decided to buy an Ultra Luxury model. Sold my 2005 ML and bought a 2004 UL with 80K. Everything seems to work however I have notices that the air pump for the air suspension comes on every once in a while. (Runs about 30 seconds a short time after starting the car and then won’t run again on a 1/2 hour drive) Does this sound normal or is a slow leak possible? The user manual really doesn’t much. The ride is nice and soft.

BigBoomer

Sounds normal to me. Mine does it too.
The compressor keeps the system at operating pressure.
Over time a little leaks out so it tops it up.
It's why there is a compressor fitted.

aypues

No, not normal. The air pump should be totally inaudible. The air pump has bushings in its mounting to isolate the noise when operating. Those bushings likely need to be replaced (a few hundred dollars to do at Lexus, cheaper elsewhere). If there is an air leak somewhere in the system that should be checked and fixed too, but when operating the pump should be imperceptible.

lextout

[QUOTE=aypues;11195984]No, not normal. The air pump should be totally inaudible. The air pump has bushings in its mounting to isolate the noise when operating. Those bushings likely need to be replaced (a few hundred dollars to do at Lexus, cheaper elsewhere). If there is an air leak somewhere in the system that should be checked and fixed too, but when operating the pump should be imperceptible.[/QUOTE

Spot on

StanVanDam

I hear my air suspension pump maybe 4 out of 10 cold starts after many days of sitting, but I also have above average hearing and know what to listen for. Unlikely anyone I know would ever hear it or recognize it on their own. Sounds like a low burble/gurgle, can only hear it in dead silence, and it stops after 5-15 seconds. I've never heard it while driving or stopped, but maybe because I'm always listening to music after I safely unpark the car.

My air suspension calibration was performed perfectly by the local Lexus dealer 12 years ago, and I assume they checked for leaks when I took it back to them 3 times to calibrate properly, which was also after they replaced the height sensors after I got rear-ended.