High pitch metallic ringing while driving, revving in park

[brightblack123]

Hello,

Long time viewer, first time poster. Happy to be here.

I just ran into a bizarre issue at 20k miles. High pitch metallic ringing sound coming from the engine. It doesn't matter what gear I'm in, sound comes off and on when gas pedal is depressed. Also happens while revving in park (which ruled out the common drive shaft bearing issue for me). I don't think it is is the intercooler tube either, just based on the metallic sound - but I will hopefully have a look tomorrow.

Took it to the dealer today and of course it was heavily raining all day and for whatever reason, I was unable to recreate the noise on-site. They did a quick overview of the tubes and belts and pulleys and everything looked good. I'm to bring it in once the noise is back (happened consistently on my way back home after their closing hours).

It feels like this happens when the truck is fully driving and warmed up a bit. Sound occurs almost the entire time of my 45 minute commute.
I figured I'd post here to see if anyone had a similar issue and could suggest a starting point.

Thanks!

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[RangerBill]

Hello,

Long time viewer, first time poster. Happy to be here.

I just ran into a bizarre issue at 20k miles. High pitch metallic ringing sound coming from the engine. It doesn't matter what gear I'm in, sound comes off and on when gas pedal is depressed. Also happens while revving in park (which ruled out the common drive shaft bearing issue for me). I don't think it is is the intercooler tube either, just based on the metallic sound - but I will hopefully have a look tomorrow.

Took it to the dealer today and of course it was heavily raining all day and for whatever reason, I was unable to recreate the noise on-site. They did a quick overview of the tubes and belts and pulleys and everything looked good. I'm to bring it in once the noise is back (happened consistently on my way back home after their closing hours).

It feels like this happens when the truck is fully driving and warmed up a bit. Sound occurs almost the entire time of my 45 minute commute.
I figured I'd post here to see if anyone had a similar issue and could suggest a starting point.

Thanks!

Could it be a loose shield on the exhaust system?

 

[airline tech]

I hear a very faint sound of (Belt Squeal) Moreso a cracked belt squeal.

 

[Capt Jon]

Sounds more like a bearing squeal, like an alternator or maybe water pump.

 

[HeatXfer]

High-speed, thin metal sound. Sounds like metal-on-metal to me. Have an assistant bring the revs up until you hear the sound and work your way around the engine with a length of hose, tubing, or use a long-handled screwdriver to narrow down and hopefully pinpoint where the sound is coming from.

 

[Retirednavy2010]

Does the frequency change as the motor is revving? Also if it couldn't be recreated when wet could be a belt. Just for shits and grins pour some water on the belts while running and squealing and see if it changes? If no change, spray some wd 40 on the belt tensioner bearing while it is stopped and then repeat the reving and see if it changes.

Sounds more like a bearing squeal, like an alternator or maybe water pump.

 

[brightblack123]

Does the frequency change as the motor is revving? Also if it couldn't be recreated when wet could be a belt. Just for shits and grins pour some water on the belts while running and squealing and see if it changes? If no change, spray some wd 40 on the belt tensioner bearing while it is stopped and then repeat the reving and see if it changes.

It doesn't change frequency -- which is strange. It's fairly constant when it's happening. Today while driving, it would stop when I took my foot off the gas, would engage when I accelerated. It got progressively more frequent as I was driving and after I parked, it continued while I was idling. Once I left the store to drive back home, it didn't happen at all except when I really laid on the gas (hill or otherwise).

Haven't had much time to poke around at it, but will definitely circle back asap. I did open the hood to try and pinpoint the location, but it was impossible. It actually sounded like it was more towards the back of the engine -- but I can't really tell. Going to try the water test shortly.

 

[HeatXfer]

It doesn't change frequency -- which is strange. It's fairly constant when it's happening. Today while driving, it would stop when I took my foot off the gas, would engage when I accelerated. It got progressively more frequent as I was driving and after I parked, it continued while I was idling. Once I left the store to drive back home, it didn't happen at all except when I really laid on the gas (hill or otherwise).

Haven't had much time to poke around at it, but will definitely circle back asap. I did open the hood to try and pinpoint the location, but it was impossible. It actually sounded like it was more towards the back of the engine -- but I can't really tell. Going to try the water test shortly.

I think the fuel pump runs at a constant speed, might have something to do with pressure changes/fuel delivery?

 

[Retirednavy2010]

It doesn't change frequency -- which is strange. It's fairly constant when it's happening. Today while driving, it would stop when I took my foot off the gas, would engage when I accelerated. It got progressively more frequent as I was driving and after I parked, it continued while I was idling. Once I left the store to drive back home, it didn't happen at all except when I really laid on the gas (hill or otherwise).

Haven't had much time to poke around at it, but will definitely circle back asap. I did open the hood to try and pinpoint the location, but it was impossible. It actually sounded like it was more towards the back of the engine -- but I can't really tell. Going to try the water test shortly.

If the water proves inconclusive I'd let the truck cool and roll underneath and look at the catalytic converter shield between the cat and the cab look for any shiney wear spots. Maybe take a screwdriver and take the handle and tap around the exhaust and heat shields for anything loose. When i worked in the auto industry NVH (noise, vibration and harmonics) was the toughest battle to isolate noises.

 

[canyonslicker]

A wise Ford engineer, Phil that used be on here but hasn’t been seen due health issues. suggested to get a cheap stethoscope and remove the diaphragm to use as a diagnostic and directional listening device.

 

[Cabose-1]

Take off the belt and check belt tensioner.
Do not mess with the ac belt. Special tool to put in belt.
Check other pulleys. See if they feel stuck or do not turn smooth.
Run with belt off see if noise goes away

 

[Retirednavy2010]

Inquiring minds want to know, did you find out the issue or what caused the noise?

Take off the belt and check belt tensioner.
Do not mess with the ac belt. Special tool to put in belt.
Check other pulleys. See if they feel stuck or do not turn smooth.
Run with belt off see if noise goes away

 

[brightblack123]

Thanks, everyone for chiming in. I was hoping for a more compelling update.

I commute daily, about 45 minutes each way by highway -- I was sure I would need to make another appointment at Ford and was anticipating this sound to endure through the week. But this week - the sound has gone away. I'm not sure if that's good or bad -- and from the video you can hear how loud and bizarre the sound was. Either something was gravely wrong or loose and this item has released itself during transit -- Or during my recent 'the works' at the Ford dealership, they spilt a small amount of oil in that vicinity and it cause an aggressively squeaky belt.

I'll be sure to keep this chain updated if/when I find out what this was all about.

Thanks again for checking in and for all the suggestions.

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