Took my car in for the 30k service yesterday (is $1400 correct?!?!?), and when I go to start my car today...completely DEAD battery. Cadillac roadside, to their credit, came out VERY quickly, diagnosed the battery as dead and replaced it. Got to work and noticed a hissing noise coming from the rear, like I'm losing air out of the driver's side rear, only I'm NOT losing air.
Started the car at 12:30, came back to work and heard the hissing again after parking it. Tried to start the car at 2:30, and it's completely dead again. Caddy roadside responded quickly again, and again replaced the battery. The car doesn't make the hissing noise when it's just sitting running for a long time, and then you turn it off; only when you drive it.
The dealership also did the pinion seal recall while it was in there.
Any idea what's going on here? This is very frustrating as tomorrow is Sunday and I'll have to pay for a rental in hopes that the dealership will reimburse me. I'm going to have it towed to the dealership tomorrow if the battery is dead again.
Help please. Thanks, in advance.

$1400 for what?????

4 hours since I parked the car; just checked it and the noise is still going on. I stuck my head under the rear bumper and it seems to be coming from somewhere near the gas tank. it now sounds more like a fan noise than a hissing noise.
The "30k mile service" included:
Tranny flush, brake flush, new fuel filter, fuel injection flush, engine decarb (what a rip!), throttle body flush, cooling system flush, power steering flush, oil change w/Mobil 1 and "desludge", A/C evap & vent "deodorize", 4 wheel alignment.
Parts: $452.46
Supplies: $60.00
Hazardous Waste: $2.00
"Lab - Mechanical": $919.87 (labor?)

Sounds like the fuel pump is still running.

That's kind of what I was thinking too, but what would cause that? Also, wouldn't that flood the car out? When it's running, it runs fine.

Won't flood the car.

Will kill the battery.

Pull up the rear seat and you can get fuse access.

The fuse or relay is either there or under the hood, I just can't remember.

The hissing may be the return line to the fuel tank.

Pull the relay or fuse and see if the noise stops.

Also, I think you got a "hose" job to.

will a fuel pump drain the battery in 1.5 hours?

i've left my brights on, with the engine off, for an hour before (in my other car), and still started it without a problem. a fuel pump doesn't suck THAT much juice, does it?

I believe your 'hissing' noise is from one of the snakes in the service (??) dept. where you took your car, who is still squirming around, looking for something else to fang you with.

Yeah, I know I got hosed; I knew it as soon as he told me how much it was and what it consisted of, but I'm trying to establish some sort of relationship w/one of the 3 dealerships here so I don't get hassled w/warranty work. I took it to Legends Cadillac since they were recommended to me by someone here on the board who had a modified V and claimed to have no warranty issues w/them before. I'll have them fix this issue and see where we go from there.

I wonder how you do a throttle body flush....
I agree it's probably the fuel pump

Funny, I thought the same thing. It would be a little easier for them to cover if they just call it a "clean", but oh well.

I think those who have suggested that the fuel pump is continuing to run are correct. However, this should not flood the engine, as fuel is delivered only when the injectors are opened by the fuel injection system. A dead battery is certainly a possibility if the fuel pump does not shut off. Otherwise, there should be no other problems.