Community Forums

Rebel4x4 · 09-26-2016, 04:41 PM

I'm curious to see how often the compressor should kick on. Mine appears to turn on and off every couple of minutes. At least I believe that it is the compressor, kind of a high pitch sound.

Anyone else have this issue? Kind of annoying because it does it so often.

DMTTRANSPORT · 09-26-2016, 04:51 PM

More annoying would be the cost of a new one, air leak, governor issue or the air dryer.

Rook · 09-26-2016, 06:16 PM

My compressor does not make any sound. The only way I know it is "on" is to see the air pressure rising. Rook

twinboat · 09-26-2016, 06:28 PM

Can you describe when you here this noise ?
Driving, parked, up hill or down.

I've been working on air systems for 45 years and can't recall hearing a high pitched noise from a compressor.

If it is cycling often, it would blow a blast of air, from under the rear axle area, every cycle.

Rebel4x4 · 09-26-2016, 07:21 PM

Quote:

Originally Posted by twinboat

Can you describe when you here this noise ?
Driving, parked, up hill or down.

I've been working on air systems for 45 years and can't recall hearing a high pitched noise from a compressor.

If it is cycling often, it would blow a blast of air, from under the rear axle area, every cycle.

I hear it anytime the engine is running, whether parked or driving. It sounds as if an electric motor is running. It runs for about thirty seconds, shuts off for a minute or two, then starts back up again.

I'll have to try timing it and see if I can pin point where it is coming from. Sounds like right under the drivers area.

JaminSamin · 09-26-2016, 08:01 PM

I think you're talking about the vacuum pump that provides vacuum to the various HVAC actuators. Mine cycled frequently until I found and fixed a leak in the blue vacuum hose. Now it cycles a lot less, I don't even notice it anymore. You most likely have a leak too.

**Lt Dan** · 09-26-2016, 10:10 PM

Quote:

Originally Posted by Rebel4x4

I hear it anytime the engine is running, whether parked or driving. It sounds as if an electric motor is running. It runs for about thirty seconds, shuts off for a minute or two, then starts back up again.

I'll have to try timing it and see if I can pin point where it is coming from. Sounds like right under the drivers area.

That sounds like the condenser fan for your dash air conditioner. To confirm this, just turn off your AC and see if the noise stops. My condenser is directly under the driver's area, as is the one in my friend's 2014 Fleetwood Excursion. If you look underneath, you'll see two electric fans on the front of a radiator looking condenser coil. When you are moving and there is enough air flow, the fans won't run but they will run when sitting still or driving slowly.

Your air compressor will be a sort of clattering sound at the rear since it's on the engine. You will hear it bleed off air and quieten down once it reaches full pressure.

Kiawah · 09-30-2016, 08:56 AM

+1 on what Dan said.

It's your dash air conditioner.

Turn off your air conditioner, and you will hear it stop. You will soon "tune out" / ignore that sound.

ru499 · 10-06-2016, 11:56 AM

Look under the front hood. You'll see a round vacuum tank about the size of a softball. Check the vacuum hoses for a leak.

What you're hearing is the vacuum pump running.