I don't know what it could be,
but, my wife hears the same thing!
I tell her, we must have an air mattress,
but we don't?
:)
In a message dated 2/16/04 9:16:03 AM Mountain Standard Time,
roadguy@ROADHAUS.COM writes:
Volks,

Ok .. so there I am last night,  peacefully sleeping at around
mid-night.

The only sounds are an agitated surf breaking against the beach.

When all of a sudden I hear "Push" the sound of suddenly escaping air or
some other substance that was under pressure.

Definitely coming from outside and from somewhere in the front of the
vehicle.

Shoot, I Think, One of them damn Raccoons or Nutria chewed thru a tire:)

After maybe 60 seconds it stopped.

Finally gathering enough courage to explore the depths of the darkness
... I grab the ole trusty Mag light and hit the ground.

All tires look normal.

The night is deadly quiet.

Back in the Van I spend the next couple of hours tossing and turning ...
trying to figure out what it could have been.

The spare tire I think. It had a plug in it, maybe the plug suddenly
gave way. But why only 60 seconds of escaping air.

This morning I check the spare ... it's fine and fully inflated.

The othe thing I thought of was one of the LP tanks had some sort of a
release.

Checking both tanks ..... They both are still unmder pressure ... Of
cours ei can't tell if they lost and gas or not.

But they both still have gas in them.

Is there any reason one of them would have had any kind of spontaneous
release?

A pressure build up due to temp, humidity, barometric pressure ...
Anything?

If not, does anyone have any idea what else could make such a sound?

It's kind of like the air release on some vehicle with air brakes.

A quick, short release of pressure.

I'm stumped.