Irritating Vacuum Assist

[Abstract Art]

Anyone know what I'm talking about? It comes on my year car and makes alot of noise, its hard to describe, it basically sounds like an air pump for a compressor. It drives me nuts sometimes, not necessarily when driving, but when I'm parked, it echos off all the surrounding cars and makes my car feel like more of a pos then it is. Anyone know how i can minimalize if not complete get rid of this annoying sound?

 

[Jody John Sakstrup]

That air pump sound

My 91 DeVille makes the same sound, but barely noticeable, after I shut the car off and there's a load in the trunk or passengers are getting out the back seat. It's the air compressor for the rear air shocks adjusting, and is doing its job I've been told from my mechanic.

Yours is malfunctioning if its really loud; shouldn't be more than a murmer when listening. Does it happen when the engine is running or right after you shut it off? Either way, it needs to be replaced. And nothing is cheap on these Caddies...let me tell you.

 

[DaveSmed]

You have to have either a 85 or 86 to have the electric vacuum assist. This pump ONLY runs when the car is running (maybe with the ignition on) BUT not when parked. The pump that runs with the car shut off and parked would be the ELC compressor for the rear suspension. You likely have had a leak in the system, and the pump just plain wore out. You can verify that it is the ELC compressor by opening the hood when it is making the offending noise. The vacuum pump IIRC is under the battery tray, while the ELC compressor is out in the open on the drivers side by the inner wheelwell.

 

[Abstract Art]

it only makes it when the car is started or the ignition is on. and i can only hear it when i have the windows down and I'm driving down a street with fences on both sides or parallel parked cars on both sides and the sound bounces back at me. Some guy at the dealership says they all make it?? well that year anyways, i dunno