I few weeks after I got my XKR I had to stop in a parking lot to sit in on a conference call. It was about 95 degrees out so I left the engine running as I listened in on the call. After about ten minutes I heard what sounded like a truck's Jake Brake, or a very low whoopee cushion, from the right rear of the car. At first I thought it was actually a truck. Then it happened again a few minutes later. And again. It would happen every five to ten minutes. It had to happen about 3 or 4 times before I finally realized it was coming from my car.

Now, every time I stop and let it idle for ten minutes or so, I'll hear that sound. What could it be? It's obviously coming from the right rear. My wife heard it and she thought it was a truck. She also said it was from the right rear.

It basically sounds like a very low fart that last about one to two seconds and gets lower and quieter with time.

I was thinking that maybe it has something to do with the fuel system pressurization, like a relief valve or something, but I never smell gas fumes, so... Any thoughts?

 

Hey, a new problem! Never heard anything about this before, ever.
I eagerly await any worthwhile responses, since this post of mine is utterly worthless.

 

Really cant think Rev sam , hope others can help

 

I can't tell if you're being serious, or telling me I should have used the search feature. ¯\_(ツ)_/¯

 

Just throwing it out there but could it be some of the electronics in the right rear, ie nav unit ect. making noises

 

Cats having a fart lol

 

Well, the XKR has a vacuum pump and tank for the active exhaust operation, but I thought that was on the left rear, behind the wheel, but I could be wrong, I only have an XK.

 

Top man , could be that

 

This is definitely coming from the right side, and it's muffled, like it coming from outside of the car. At least that was my first thought. I told a friend about it. He knows nothing about Jags. At all. He immediately said "duck valve". I was like "WTF???" I had never heard the word duck used in relation to cars until I got my XKR, and now I've heard it in reference to two different things. I googled "duck valve" and found out it's actually called a duck bill valve, and that's what is used on the AC drain. But the sound I'm hearing is obviously not the AC drain.

Tomorrow I might put a microphone on the back right side, let the car idle, and see if I can get a recording of it.

 

By the way... if anyone here listens to Glenn Beck, at the end of each segment when he's cutting to commercials he plays an almost identical sound. It's mixed in with the outro music. Right at the end, a moment before he cuts to the commercial, there's a very low "BRRRRRR". That's the sound I hear. But I hear it even when the radio is turned off.

 

Yeah try take a recording . sure most duck bill issues were with the 4.2 l cars but cant be certain if the 5l cars are affected

 

I'm no help Rev Sam. I looked up the modules in the right rear. Other than the Nav Module, the Fuel pump driver module is down near the evaporation canister but have no idea if it makes noise (rattling in a bracket)?

Heck I had to Google Glen Beck.

 

Can't say I ever heard it on mine, but the nav, module contains a DVD and from your description it sounds a bit like a DVD spin-up or spin-down.

 

Here's the source:

 

How about an update Rev Sam? You had the road trip. Has it happened again?

 

I only hear it when I'm sitting in a parking lot idling for 10 minutes or more. This past weekend was kinda busy. I'll try to get a recording of the sound this weekend. (No promises. I might have to golf or something.)

 

Golf is Mandatory!

 

Just a suggestion from someone that knows nothing. The gas filler cap is in the right rear and the fuel system is closed as we get an message if we leave the cap off or not tight enough, But would guess it has to vent somehow.