Anyone know what this noise could be?
This occurs after engine is hot, the sound starts about 30min to 1 hour after shutdown and lasts for about 20min.
2018 F150 5.0 with 500 miles.

 

Sorry, but your post really lacks clarity. Just what are you asking? Is it making noise after bring off 25 minutes?

 

Having trouble posting video

 

Fuel pump priming when you open the door.

 

There are a bunch of things that operate after the vehicle is turned of (regardless of engine). There is the evap control system, the front shutters, and I don't know what else. I am not surprised so much as curious when I hear these things after I turn the truck off. After 30-60 seconds most of these things settle down.

 

Thanks for the replies. The forum wont let me download mp4 for some reason.
The noise isn't the fuel pump pressurizing after opening drivers door.
it's a high pitch squeal that starts a few minutes after shutting down and will last roughly 10 to 15 minutes.

 

Just added the audio

 

Are you saying the dealer can’t figure it out?

 

Had them listen to recording, they had no idea. It's not consistent enough to take truck in.

 

That is a strange one. Here's a WAG: It's something that gets hot. Cat, muffler, the pipes. That something is welded. That weld has a flaw. Gases flow into a void until heat expands it, temporarily sealing it. Upon cool down, it opens up, and whatever gases are in there escape with the whistle sound.

Seal all known openings in the truck. Run to operating temperature. Submerge truck in water, and observe the exhaust system as it cools down. If this is impractical, try checking any welded joint in the exhaust while the noise is happening. If you can get one, a thermal imaging device might help.

Another WAG: Something to do with EVAP, possible any purge device. A schematic of the EVAP would tell that tale, and any suspect item could be observed close up.

How close is your drive shaft to the exhaust? That's a welded item with a big void to hold pressure under the right circumstances.