Took the 2012 XK out for a winter reprieve today and all was well. Stopped to fill her up and continued on my way home. As I was driving (70mph) a weird noise started emanating from the center counsel. It sounding like a flat horn. It did it four or five times. I have never experienced this before and wonder if it was a form of alarm. The engine temperature showed 195 degrees. Any idea as to what this might be. Thanks.

 

Probable a mouse screaming because you were driving to fast.

 

You ran over a plastic bag and it got stuck under the car, fluttered in the breeze then blew away.

 

chiefmd,

Did that noise change in volume or pitch as your speed changed? When you stopped, did you look under your car for any debris that might have accidentally gotten caught there? A foreign object rubbing up against a rotating driveshaft is a possibility.

Your XK apparently had been garaged for some time. Maybe she was complaining about the cold.

And the rubbing.

 

Put the car on the lift and removed the lower panels and everything is fine, no plastic bags. The noise would last a couple of seconds and go away then return a few seconds later, Did this 3 or 4 times. The noise level didn't change in pitch just a low "flat horn" sound.

 

Since there were no foreign objects underneath, maybe something is loose that is vibrating and causing resonance. Put it back up on the lift and shake the exhaust pipes and whatever else you can think of and try to find the cause.

If nothing is loose, then maybe that sound is caused by undercarriage airflow - like a reed instrument. Try replicating that sound by driving without the belly pans.

It's tough to solve a strange noise problem when the car is running fine and there are no codes.

 

Well, with time it will either get better or worse. Since you haven't found anything obvious I'd let it go a little while.