2020 Explorer ST Humming/Rattle When Accelerating

mcfarlrm · Jan 20, 2022

I recently purchased a 2020 Explorer ST and have been noticing a humming/rattling noise coming from the left engine bay right underneath the dash. This only occurs when accelerating in any driving mode. I had the Ford dealership look at it and they said it was a normal and coming from the wastegate. Has anyone else notice this or heard of someone noticing this? Want to make sure they are not shrugging off a larger issue.

TMac · Jan 20, 2022

There are a number of issues with both cracking welds on catalytic converters and flex pipes. First thing is when a dealership tells me it's "normal and coming from the wastegate", I'm going to roll my eyes.
However, when you say accelerating, are you saying full throttle, or just any type of acceleration? Under acceleration, there is movement of the engine under torque- which is likely leading to contact between components (exhaust, etc) causing the sound.

mcfarlrm · Jan 20, 2022

TMac said:

There are a number of issues with both cracking welds on catalytic converters and flex pipes. First thing is when a dealership tells me it's "normal and coming from the wastegate", I'm going to roll my eyes.
However, when you say accelerating, are you saying full throttle, or just any type of acceleration? Under acceleration, there is movement of the engine under torque- which is likely leading to contact between components (exhaust, etc) causing the sound.

mcfarlrm · Jan 20, 2022

The sound is coming form another location other than the flex pipe, which I also noticed and was able to pinpoint immediately. The low level humming noise is just any type of acceleration and coming from the engine bay itself. I tried looking up video's to see if there are examples and can't seem to find one that shows a clear example. I will try to make a video where you can hear it.

TMac · Jan 20, 2022

Being honest, no sound recording is going to allow someone to diagnose this problem. There are literally scores of things that could be suspect. The two most difficult things to diagnose are noises and electrical gremlins. Dealerships, especially in warranty situations, aren't going to spend a lot of time tracking these things down because there's no money in it and why they tell you that "it's normal". Here are your choices: learn to live with it until it get's so bad that an actual problem surfaces that can be accurately diagnosed, or camp on your dealership's door until they either fix it to your satisfaction or hand you another vehicle.

mcfarlrm · Jan 20, 2022

My thoughts exactly. Just didn't know if this was someone common with other ST owners and could be pinpointed based on my description alone. I'm going to take it to another shop other than where I purchased it so wee if they can determine what's going on.

hbalek · Jan 20, 2022

mcfarlrm said:

Did you notice it on the test drive or after you took it home? I would suggest driving another ST to see if it really is characteristic of the vehicle.

mcfarlrm · Jan 21, 2022

I did not notice it on the test drive and it was one of those small nuances that you end up noticing after the fact. I will ask to test drive another ST when I am at the dealership.

marksst · Jan 23, 2022

I've noticed mine, only twice now, sounds like a super charger whining/screaming on full acceleration. I just call it demon mode, haha. It really sounds like the hellcat...ha.

Sent from my SM-N981U using Tapatalk

Mazzoo2012 · Mar 9, 2022

mcfarlrm said:

I recently noticed this soft buzzz noise when letting off the gas as well. I haven’t taken it in yet, it’s getting serviced Friday I will mention it then. Anyway, did you get it figured out?

mcfarlrm · Mar 10, 2022

Mazzoo2012 said:

The noise still persists and two Ford dealerships said it was normal, which I still don't buy. I'm going to take it to a performance shop to see what they think. The noise I hear is when accelerating, not when letting off the gas. You might be noticing the turbo blow off. The noise I notice is a low level rattling/humming noise when the RPM's rise while accelerating in all gears and drive modes. Almost like the sound of when you put a playing card in a bicycle wheel.

Mazzoo2012 · Mar 10, 2022

mcfarlrm said:

ahh I see, I hope the performance shop can figured it out for you. mind is not severe or as noticeable with radio/music in the background. Just one of those things once you noticed can’t stop hearing. Does sound like wastegate issue.

mcfarlrm · Mar 10, 2022

Mazzoo2012 said:

I'm thinking it might be a lose component on the waste gate and Ford may be brushing off the issue or just not looking at it since it's under warranty and probably won't touch it until complete failure. I don't think it's the turbo since I'm not losing any power, no oil burning off, etc. Then again, I'm no expert...

barackus · Mar 11, 2022

Don't buy the normal BS from the dealerships. I will miss my 21 ST (Bought in Nov of 20) significantly - but the quality just isn't there IMHO. My problems in the 15 months that I have owned it in order

Defect in the lift gate glass caused cracking - fixed
Transleak - tailshaft seal as well as cooler seal - fixed
Sync problems - rear camera - fixed
Sync problems freezing - not fixed
Sync app no pairing anymore - can't reset connectivity - I'm SW engineer(an gearhead) so I know what I am doing - not fixed
Vibration at 60 in the steering wheel and only around that speed - not fixed
Vibration in the vehicle b/w 8-1100 rpm - continue reading

Forgetting sync absolutely sucks - and I could live with the quirks. The vibration issue experience made me pull the buy back trigger.

Flex pipe rattling will vibrate the entire exhaust which resonates through the vehicle
Tech called ford and said "crank imbalance" and engineering instructed them to replace the long block.
New engine put in vehicle - vibrations still exist(shocked I was).
Tech called Ford and said when they disconnected exhaust from the cats that vibration stopped(again shocked!).
Ford approved replacing from the cats back -2 week wait.
New exhaust arrived and tech noticed that there was rod knock in the new long block.
Tech inspected the oil and found it to be nice and glittery and the filter looked like a disco ball.
Ford said to replace long block (and no to the turbos).

Buyback approved and seems to be going smoothly. Wont get another exploder as tempting as it is -don't feel like paying the 3k difference in MSRP to get back to where I was. 15k MIles

So, push on these guys telling you the issues you have are normal. They are not!!

Mazzoo2012 · Mar 19, 2022

mcfarlrm said:

I think you’re right, it only happens when letting off gas and waste gate would be one of the things opening/closing during this time. I’m no experts either but sometimes common sense is unbeatable.

However, I took it to the dealership to get serviced and told them about the issue. They took it for a driver but they couldn’t hear it. So, I brought it back and took one of the mechanics on a drive to demonstrate when it happens while driving. Got him to hear the clicking/rattling noise behind the dash as he takes his foot off the gas. He told his manager that he was able to hear the noice this time.

Then, the said this could be very difficult to diagnose since it only happens driving the drive. For now, it’s scheduled for diagnostic at the end of the month.

If this rattle get fixed I might be able to enjoy driving it. it’s all I hear even when my wife is driving it.

mcfarlrm · Mar 29, 2022

Got my ST back from the dealership today to replace the cats on an open recall. The humming/rattling noise must have came from the cracked cats. Haven't heard the noise since I drove it off the lot this morning.

Mazzoo2012 · Mar 29, 2022

mcfarlrm said:

That’s great news! Hopefully it stays that way.

mcfarlrm · Mar 29, 2022

Mazzoo2012 said:

Hoping that Ford corrected the cat issue with a new/modified part so it won't happen again.

CareerFiremanGuy · Apr 18, 2022

Has Ford fixed the flex pipe/cat issue on the 22 models?

With 500 miles on the odo, I heard a soft "rattle" a few times on start up. Went away after a short drive.

CareerFiremanGuy · Apr 19, 2022

Okay, I just confirmed that the rattling flex pipe issue still exists on 22 model ST's.

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2020 Explorer ST Humming/Rattle When Accelerating

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