loud tinkling rattle from engine at idle

[Left Coast Geek]

I chose to upgrade my 2016's Sync3 and Nav maps tonight after dark, when the temps cooled down from the 95F high today to a sane low 60s/upper 50s. The maps update required letting the truck idle in my driveway for nearly an hour. When I went back out there, there was quite a loud tinkling sort of rattle, seemingly from the front of the engine. I popped the hood and didn't see anything obvious, no leaks or anything. It did NOT sound like tappet noise, or cylinder pinging, engine temps were nominal, nor did I smell anything out of the ordinary. If anything, it sounded like a chain rattling.

It was too dark out there to see much, I'll give it a better eyeball tomorrow.

 

[Mr Big]

I chose to upgrade my 2016's Sync3 and Nav maps tonight after dark, when the temps cooled down from the 95F high today to a sane low 60s/upper 50s. The maps update required letting the truck idle in my driveway for nearly an hour. When I went back out there, there was quite a loud tinkling sort of rattle, seemingly from the front of the engine. I popped the hood and didn't see anything obvious, no leaks or anything. It did NOT sound like tappet noise, or cylinder pinging, engine temps were nominal, nor did I smell anything out of the ordinary. If anything, it sounded like a chain rattling.

It was too dark out there to see much, I'll give it a better eyeball tomorrow.

Could it be coming from the turbo?

 

[Left Coast Geek]

Dunno. Not sure I can even see the turbos on this thing without removing engine covers.

 

[Left Coast Geek]

I know videos don't really work well for diagnostics, but here's the rattle.

2024-07-06 2019 3.5L Ecoboost rattle

www.youtube.com

 

[Fastcar]

Grab a 2 foot extension, put one end on the turbo and the other against your ear. A poor mans stethoscope

 

[Left Coast Geek]

I tried a hardwood dowel, about 1/2" in diameter with a domed end, about 2 feet long... inconclusive. I note the pitch and speed of the rattle does NOT change with engine RPM, so now I'm really wondering wtf this is.

 

[apex96]

Sounds like the AC clutch/ idler pulley going south… turn the A/C on HI and then off and see if the noise stops.

 

[Left Coast Geek]

no AC vs Max AC, no change in the sound

 

[Left Coast Geek]

I tried putting it in drive with the brake on and a bit of gas, nada change. ditto in 4A and 4L, revving it to 2000 rpm or so (4L wouldn't go higher at a hard stop), no change other than the clack sound of the 4L engaging/disengaging (while in N, of course)

 

[DCaretaker]

There used to be a heat riser valve in the exhaust manifold that could produce that sound. Don't know if these high tech engines still have them.

 

[Left Coast Geek]

well, as this is my primary vehicle, I decided to drop it at the local dealer for diagnosis, since its on a CPO Platinum warranty. I got there just as they were opening, I didn't have an appointment, but the advisor assured me they would at least diagnose it by end of day.

 

[Meeker]

I would have suggested this is the turbo wastegate rattle - search for it, there's a few videos on putting a small spring on it to eliminate the rattle. Not sure it's worth it unless you're really annoyed by the sound.

 

[Left Coast Geek]

I would have suggested this is the turbo wastegate rattle - search for it, there's a few videos on putting a small spring on it to eliminate the rattle. Not sure it's worth it unless you're really annoyed by the sound.

its pretty loud. as I was checking into the dealer service this morning, I was in the drivers seat, advisor had his clipboard, I start explaining the noise, then say, oh here, and reach over and hit the Start button, RATTLECHINGRATTLECHINGRATTLECHING, and he was OH, yeah, ok, thats obviously loud.

I would have expected a wastegate rattle to change while driving, like accelerating to freeway speed... I had the radio off and my ears on driving to the dealer, and didn't sense any change accelerating to freeway speed.

 

[Left Coast Geek]

and.... shop found a little scrap of metal had fallen behind the water pump pulley and was rubbing against it. it fell out when they poked at it, and boom, sound gone.

no charge.

 

[D Hook]

Go by a lottery ticket. You'll probably win with that kind of luck!

 

[Left Coast Geek]

Go by a lottery ticket. You'll probably win with that kind of luck!

I'm assuming the labor was covered by the CPO/ESP thats still in effect (we paid for the 100K mile version). The advisor said they removed the serpentine belt, identified the water pump pulley as the noise source and removed said pulley, and thats when the metal bit fell out, so they put it all back together and gave it a quick test drive. I probably should have clarified that in my last post. I can't imagine R&R on the serpentine belt taking less than an hour as all the turbo air plumbing is in the way.