New 2023 Odyssey Elite, mysterious knocking noise when the gas tank is between two-thirds and completely full.

768 Views 16 Replies 5 Participants Last post by 2023Elite, 13 d ago

2023Elite

Discussion Starter · 16 d ago (Edited)

2023 Odyssey Elite with 5000 miles, there is a mysterious thumb knocking noise when driving over bumps or uneven roads:
1. the noise is near/around the middle-right side of the second row seats.
2. the noise is ONLY triggered by when the gas tank is between two-thirds and completely full, it doesn't matter how many passengers there are.
3. the noise completely disappears when the gas level is below around two-thirds or half.

1 - 17 of 17 Posts

digitalextremes

· #2 · 16 d ago

Check your shock/strut to see if it’s leaking. Mine did the same and it was the leaking strut that I replaced to solve the issue.

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2023Elite

Discussion Starter · #3 · 16 d ago

digitalextremes said:
Check your shock/strut to see if it’s leaking. Mine did the same and it was the leaking strut that I replaced to solve the issue.

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Thanks, I just checked all 4 and none are leaking.

dvpatel

· #4 · 16 d ago

What does your local dealer have to say about the issue?

2023Elite

Discussion Starter · #5 · 16 d ago

dvpatel said:
What does your local dealer have to say about the issue?

After filling up the tank, I went to the dealer and waited for three hours. Then they told me they couldn't hear any noise.

Reactions: 1

2023Elite

Discussion Starter · #6 · 16 d ago

During the day, I'm busy with work, and at night, I'm occupied with fixing various interior noises in this new Odyssey. Recently, I just fixed the driver's side B-pillar rattle.

I meticulously inspected and secured all the interior components, from front to back, left to right, even reinforcing the ventilation ducts beneath the carpet. This noise is caused by a loosely fitted object that's impacting something. It's unlikely to originate from the interior components I thoroughly checked. I now suspect it's coming from beneath the car chassis, near or inside the fuel tank, where an object might be causing the noise due to fluctuations and movement caused by high gasoline level.

Without this thumping noise from the fuel tank, the Odyssey would be the quietest and smoothest minivan I've ever owned, almost like a luxury car. Unfortunately, this problem seems to exceed my ability to repair. When I can no longer tolerate this noise, I'll go back to driving my luxury SUV, which is super quiet and smooth but has much less space compared to the Odyssey.

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DJVAN

· #7 · 16 d ago

Just like the dealers, they can't hear anything when it is under warranty! Let it be out of warranty and they will gladly charge you megabucks to find it. Try pulling out your 2nd row middle seat and see what it does with same gas tank levels, if not leave seat out and move the two outsiders into the middle of course one at a time. And no Hodna were not playing Twister!

I found that I had to recline my rear seats slightly to eliminate a dull rumble from the second row seats, rather than being straight up and down.

2023Elite

Discussion Starter · #8 · 16 d ago

I completely removed the second-row seats, including the base covers on both sides, and folded down the third-row seats, test drive with full gas, and the noise was exactly the same. After securing the ventilation pipe under the carpet, I began to suspect that the noise was coming from underneath the chassis, or even from inside the gas tank.

HondaGoBrrr

· #9 · 16 d ago

Be relentless while that car is covered under warranty. Be "that person", that will not rest or take no for an answer. Have a tech ride along on a test drive, so when the noise happens you can say "THAT!" If they still cannot hear it, have them open a case with Honda's internal service support line, if it's bad enough and they can't figure something out they will send a Honda engineer into the field to a dealership. Doesn't happen very often but I have seen one or two come to my shop in my career.

Reactions: 1

digitalextremes

· #10 · 15 d ago

DJVAN said:
Just like the dealers, they can't hear anything when it is under warranty! Let it be out of warranty and they will gladly charge you megabucks to find it. Try pulling out your 2nd row middle seat and see what it does with same gas tank levels, if not leave seat out and move the two outsiders into the middle of course one at a time. And no Hodna were not playing Twister!

I found that I had to recline my rear seats slightly to eliminate a dull rumble from the second row seats, rather than being straight up and down.

Even in warranty, dealers in Canada ask for diagnose fee to look at anything and only reimburse it if a warranty issue issue is found.

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digitalextremes

· #11 · 15 d ago

If not already done, check to make sure the spare tire is properly secured.

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Reactions: 1

2023Elite

Discussion Starter · #12 · 15 d ago

digitalextremes said:
If not already done, check to make sure the spare tire is properly secured.

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Even after I removed the spare tire and jack kit, the noise is the same when the gas tank is full.

DJVAN

· #13 · 15 d ago

@digitalextremes
Wow, for a vehicle that is under warranty there should be no charge for diagnostics at all. Knowing that they cannot find anything wrong with a ODY doesn't give them the right for charging an owner for a diagnostic fee. Like to see where in the warranty handbook where that says that, and not no later added addendum.

HondaGoBrrr

· #14 · 15 d ago

DJVAN said:
@digitalextremes
Wow, for a vehicle that is under warranty there should be no charge for diagnostics at all. Knowing that they cannot find anything wrong with a ODY doesn't give them the right for charging an owner for a diagnostic fee. Like to see where in the warranty handbook where that says that, and not no later added addendum.

The thing is though, advisors at my dealer will be like "we gotta charge up front because we don't know 100% your issue is covered under warranty". I am unsure how widespread that practice is, it might vary depending on what the concern is.

DJVAN

· #15 · 14 d ago

@HondaGoBrrr
Back quite a few years ago, working for a GM Buick dealer, the policy was if the customer had a complaint and the vehicle was under warranty (mileage & age) we never ever charge for a diagnostic fee that is charged for today. This was called customer service, and they wanted returned sales and service after the warranty was over. There was nothing mentioned in the manual about if we can not find the problem (dealer) that we would charge for something we could not see/hear/feel ourselves. Inevitably after some time would take place, the problem would appear and they would bring in their vehicle and sure enough there was a problem found. This was not an always statement, I would say if I put it to a number it would be 70% of the people would be right. Customer service was a commitment, that is why people come back to a dealer along with honesty. I absolutely hate service write-up people saying, "We have never heard of that problem, and we will check it out." The price of the dealer should be $0.00 to check a vehicle out, understanding no parts involved and only eye/ear diagnostics done. That is why it cost more at a dealer for parts, labor and shop use, to help offset the time employees expend on looking at a warrantied vehicles.

I am not saying you are part of this scheme, but charging up front doesn't take away an honesty feeling for most people.

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digitalextremes

· #16 · 14 d ago

DJVAN said:
@HondaGoBrrr
Back quite a few years ago, working for a GM Buick dealer, the policy was if the customer had a complaint and the vehicle was under warranty (mileage & age) we never ever charge for a diagnostic fee that is charged for today. This was called customer service, and they wanted returned sales and service after the warranty was over. There was nothing mentioned in the manual about if we can not find the problem (dealer) that we would charge for something we could not see/hear/feel ourselves. Inevitably after some time would take place, the problem would appear and they would bring in their vehicle and sure enough there was a problem found. This was not an always statement, I would say if I put it to a number it would be 70% of the people would be right. Customer service was a commitment, that is why people come back to a dealer along with honesty. I absolutely hate service write-up people saying, "We have never heard of that problem, and we will check it out." The price of the dealer should be $0.00 to check a vehicle out, understanding no parts involved and only eye/ear diagnostics done. That is why it cost more at a dealer for parts, labor and shop use, to help offset the time employees expend on looking at a warrantied vehicles.

I am not saying you are part of this scheme, but charging up front doesn't take away an honesty feeling for most people.

I paid $180 to a Honda dealership in Toronto to check engine noise that came up at around 80km/h. That charged me they and told me no issue found. My vehicle is in warranty. That’s a scam all Honda dealers are running these days. I never had that for a VW I owned while it was under warranty.

I came home, waited for weather to warm up a little (since I had to work on the driveway) and opened up my wheel and noticed the driver side (aftermarket) brake pad was jammed in the calliper and was not sliding at all, had to hammer it out. The noise was from the pad always rubbing with the rotor. Cleaned and lubed calliper sliding pins with silicone brake paste, Replaced rotors and pads and noise is gone.

I asked my twin sensor doesn’t work properly; sometimes it keeps going and sometimes it doesn’t come up, they said they will charge me diagnostic fee to see if there is anything wrong with it. I said forget it; I will just buy new sensor off eBay and install myself. You guys don’t get my business.

Never going back to that dealer again.

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2023Elite

Discussion Starter · #17 · 13 d ago

I found the cover of the gasoline pump under the second-row seat. It's made of thin aluminum alloy, almost as thin as paper. When I tapped on the wire, it made a drumming sound. Secure the wire with tape. After opening the aluminum cover, I saw the plastic gasoline pump connected to two fuel lines and a wire. The pipes were wrapped in soundproofing material just like my Mercedes. I stuffed as much as soundproofing material between the pump and the cover, hoping it wouldn't create static electricity and blow me up into the sky.

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