2020 PIU Obnoxious rattle - Underbody deflector

[hardware1197]

So I've been reading a lot about various rattles but this one I chased and thought I'd post the journey....

Had an annoying rattle coming from the B Piller/Door jamb area of the passengers side.

Symptoms:

• Constant at any speed above 50
• more pronounced in high wind
• unaffected by temperature
• Rattle could almost be felt underfoot while riding in rear passenger seat

The chase:
Removed B piller trim and floor trim
Removed both front and rear door panels
Used an endoscope
Built an automotive stethoscope from rubber tube and a small funnel

The culprit:
This CRAZY underbody deflector panel that is like a felt covered plastic pan that looks like it was designed at the last minute to solve some problem that not much thought went into....slapped in place with a plastic nut and some screws......I almost think that some trim is missing that allows air to sneak into the pan area and cause it ti flop up and down and random oscillations - my temporary solution was some duct tape.....that's correct.......

By the way that pan has a LOT of little rocks and debris in it at just over 2800 miles since new.......

Part in question: 7811782 (L1MZ-7811782-F - PIU Version)

I did not see any reference to this is search........

 

[peterk9]

L1MZ-7811782-F is shown as being for the Explorer 3.0 and 3.3L gas. https://parts.autonationfordwhitebearlake.com/oem-parts/ford-air-deflector-l1mz7811782f
If I'm not mistaken, that is also the position of the fuel tank.

Peter

 

[hardware1197]

Must be

L1MZ-7811782-C​

Then.....

Here's a screen grab from an ST underbody walk around walk around video on svtperformance.com

2020 Ford Explorer ST on the Rack | Undercarriage Inspection

2020 Ford Explorer ST on the Rack | Undercarriage Inspection A few months back we had the opportunity to do a full review of the 2020 Ford Explorer ST. Unfortunately, we didn’t get to spend as much time as usual with it and we missed some important content for you. Fortunately, during a...

www.svtperformance.com

Make a good bootlegging car......could hide about 40 pints of shine in there......

-Dave

 

[hardware1197]

Couple part numbers for this rattle issue:

W719929-S300 - Plastic retainer
W719609-S900 - Captive washer nut

 

[GEN6]

Thanks for the write up hardware1197.

I had the exact problem you did for the past several months, "annoying rattle coming from the B Piller/Door jamb area of the passengers side" and I found this thread while looking for a solution.

After reading your post, I crawled under my vehicle a few weeks ago and noticed many of those cheap under body pan fasteners had completely failed and the passenger side pan was basically flopping/banging up and down against the bottom of the vehicle in the wind. It would have fallen off eventually, been shredded, and landed on someones windshield.

It's very interesting that I could swear the sound was coming from the B-Post itself, inside the vehicle, but nope, it was that poorly fastened under body pan on the passenger side banging around and the sound actually seemed to coming from the B-Post inside the car like you said.

I took my Exp to my dealer and asked them to replace all of the poor quality failed plastic fasteners with METAL nuts (ON BOTH SIDE OF THE CAR), and they did.

Note: Not long after my Explorer was new, two years ago, it had an almost identical rattle that sounded like it was coming from directly under my instrument cluster. You could only hear it with the radio off (in general). It was annoying too. That problem was probably due to all of the loose hardware on the drivers side pan that I just now had fixed along with the passenger side! Here's another thread where many rattles are being reported and diagnosed.

Strange noises inside dash/engine bay caused by wind?

I was driving my XLT today and noticed a strange sound coming from the dash area or engine bay. At around 45 MPH you can start to notice something sounding like paper being crumpled. As I got faster the noise gets louder and more frequent. Its obvious that the wind is playing a factor in this...

www.explorerforum.com

Thanks again.

 

[hardware1197]

My experience almost exactly. I’m glad you were able to find it. I am still chasing rattles that I am also certain are in the A or B pillars but they almost all have been that crazy underbody felt shield. Horrible design. I also now have the insane exhaust rattle on acceleration (worse in a turn) and I’m on round three with the dealer trying to hose clamp that away.

 

[peterk9]

My experience almost exactly. I’m glad you were able to find it. I am still chasing rattles that I am also certain are in the A or B pillars but they almost all have been that crazy underbody felt shield. Horrible design. I also now have the insane exhaust rattle on acceleration (worse in a turn) and I’m on round three with the dealer trying to hose clamp that away.

Could this be the issue?

List of Useful Threads - 6th Generation Ex and Aviator Recalls, TSB, FSA and SSM

TSB - SSM 49107 2020 Explorer/Aviator Easy Exit / Entry Seats Some 2020 Explorer/Aviator vehicles built on or before 04-Sep-2019 equipped with memory seats may exhibit the driver front seat moving forward during easy entry/exit operation when the vehicle is turned off. This may be due to the...

www.explorerforum.com

Peter

 

[hardware1197]

Peter: Yes that is the exact issue....I have had two rounds of that remediation with limited results so I'm now escalated to a complete replacement of the pipes.....I should note that I had a recall performed for.....wait for it.........EXHAUST into the cabin....due to a cracked Catalytic Converter down pipe assembly. Here's the recall performed which then caused the issue that you describe above.

https://static.nhtsa.gov/odi/tsbs/2021/MC-10204044-0001.pdf

And here's good video on why the rattle TSB procedure doesn't work: