Heat Exchanger or Resonator Rattle - Worse Under Light Acceleration

[Jerome10]

I'm nearly certain that my heat exchanger and/or resonator have a rattle. It sounds like a heat shield and definitely coming from the area just under my rear passenger door. Just want to get a little feedback to help the dealer look into it for me.

It seems to occur worst when cold. Engine running even a minute or two it almost disappears, though is still faint. It is most noticeable first gear shift pulling out of garage in AM but also if the truck is running in electric, I sit at a stoplight, then fires up as I pull away from a stop light. Again I'm guessing because it has cooled down while the engine is off.

I can sometimes, but not every time, rev the engine to around 1500-1800 RPM and get the rattle while the truck is in Park. Other times it won't seem to do it. I'm not sure if that also has to do with temp or humidity or what. It also seems that sometimes when very cold outside it won't make the noise either. Almost like there is a temp range around maybe 30F when it is most common.

Lastly, it seems to be most consistent and loudest under light throttle acceleration. This is the one I'm hoping folks here can help clarify. Does it being loudest or most consistent under light acceleration tell me anything about the rattle? Like maybe it is not the resonator but driveshaft or something? Or does just that slight weight shift, or a particular frequency of vibration in the transmission or something just make the resonator noisier?

I think I've heard of some issue with a metallic noise on acceleration but it was only the V8 models... and I want to say it had something to do with the transmission. Figure the more info I can give them the better.

Anyway, any tips or thoughts on light acceleration being worse are appreciated. Plan to try to get it into the dealer soon, hopefully, before weather warms up.

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[magvallo]

Sounds like heat exchanger. I had similar issue and tried to track it down thinking it was a heat shield too. Took to the dealer and they quickly determined it was a bad heat exchanger. Dealer changed under warranty & rattle went away.

 

[HammaMan]

Didn't read your post, replying to the title. Resonator area under right temp and engine loads will rattle. Dealer will give you "can't replicate" nonsense. Haven't tracked precisely where it happens, recall it being warm, try to replicate at various temps by kicking it or hitting with a rubber mallet. Haven't isolated the conditions/location (haven't really tried sans occasional kicks). Have been a few other reports, one got the resonator swapped and went away. When I can duplicate on command or if someone else reports it, will try to replicate on command.

 

[Jerome10]

OK, yeah. Probably just more to do with temps and humidity sounds like, rather than throttle application.

Calling dealer later today.

I was looking at resonators a few days ago, thinking maybe just replace it for not a lot of money myself. Unfortunately the PB the heat exchanger and resonator are 1 part, making it hundreds more just for the part alone vs the non-hybrid models.

But the website I was looking at, it appears there have been 4 prior parts revisions before the current version of the resonator+heat exchanger. So they appear to be on #5. Says to me they've had some issues, either heat exchangers or resonator rattles.

Glad to know the dealer replacement took care of your rattle.

 

[cligon3]

I have this exact issue under same conditikns, but the dealer keeps telling me it's the wastegate rattle. They have it wrong. I just went back under the bottom to pound on some of the exhaust and I was able to get some noise coming from the heat exchanger area. I'm hoping to take it in and get it fixed but its very obnoxious for a 70k brand new truck. Really hoping not to deal with this long term.

 

[mrichard02]

I have the same exact issue on my 2024 F150 Powerboost. It is the most annoying sound in the world. I've been to the dealer and was unable to reproduce it at the dealer, nor could they so they say, but everytime i'm not at the dealer it happens. Just luck. I will keep doing whatever I can to reporo at the dealer.

Really annoying this happens on the brand new truck.

 

[jcaspar]

I have brought mine in twice for this over the past 3 years and also told it was the waste gate and normal. Would love a fix

 

[FaaWrenchBndr]

Would be nice to see some sort of a bypass/delete for the heat exchanger

 

[Jerome10]

I haven't repaired mine. Waiting for cold weather again when it gets really bad. Agree with others I am certain it is not wastegate based on where the noise comes from.

It isn't nearly as clanging as in the winter, but a couple days ago on a steep grade, gave it some throttle and heard almost like a lugging clanging sound. Much quieter but... It was in the same RPM range as the terrible metallic rattle in the cold (1800 RPM-ish).

Regarding the bypass/delete... I wonder why the resonator and heat exchanger are one single part. Why can't the resonator be removed behind the heat exchanger? Simply bridge the heat exchanger with a straight pipe? Or allow for an aftermarket resonator install.

That would at least allow replacement of a defective heat exchanger or a rattly resonator without having to do the whole single thing!

I'm also bummed that 2024 and newer trucks are having this too. Seems newer parts aren't fixing this.

 

[cligon3]

Jerome - you and I have conversed on this topic in a few threads but mine had only 1k left on warranty and I was going out of the country for a few days, so I decided to take it in and give it another try. Historically, I was told that the noise was the wastegates and that it was normal but this time, I was adamant that I was the one to induce the sound and let them take notes.

Good news... the rattle is gone! Turns out, a wiring harness above the exhaust manifolds near the left rear had a broken retainer and come loose. They fixed the retainer and wiring harness routing and all is healed.

I did not expect this, because I struggled to understand how temperature and engine load play a factor. My hypothesis is that temperature and load drive a different resonate frequency and ultimate vibration pattern that's enough to create the vibration required to strike the connector and make a noise. I didn't get good info on what exact part it was because I had to pick it up on a weekend and my tech was gone, but nonetheless, my issue is resolved.

Might be worth getting under and looking for any wiring harness connectors and inspecting their hangers. Good luck to you and the others still trying to find a fix.

 

[Jerome10]

Jerome - you and I have conversed on this topic in a few threads but mine had only 1k left on warranty and I was going out of the country for a few days, so I decided to take it in and give it another try. Historically, I was told that the noise was the wastegates and that it was normal but this time, I was adamant that I was the one to induce the sound and let them take notes.

Good news... the rattle is gone! Turns out, a wiring harness above the exhaust manifolds near the left rear had a broken retainer and come loose. They fixed the retainer and wiring harness routing and all is healed.

I did not expect this, because I struggled to understand how temperature and engine load play a factor. My hypothesis is that temperature and load drive a different resonate frequency and ultimate vibration pattern that's enough to create the vibration required to strike the connector and make a noise. I didn't get good info on what exact part it was because I had to pick it up on a weekend and my tech was gone, but nonetheless, my issue is resolved.

Might be worth getting under and looking for any wiring harness connectors and inspecting their hangers. Good luck to you and the others still trying to find a fix.

Appreciate you following up. I will see if I can dig under that for a wiring harness. When you say "left rear", did you mean "right rear"? The exhaust I believe is entirely on the passenger side after the exhaust pipes join up somewhere near the front passenger seat.

Worth a check, regardless! Glad they fixed it.

 

[cligon3]

They told me left rear and it says that on the paperwork, but I got underneath the truck after I wrote this and noticed the same you did. Clearly not left. I also wonder if they had to take off heat shields to see the harness. Ill try to get more info from the tech at some point. Wish you the best of luck.

 

[cligon3]

Jerome - you and I have conversed on this topic in a few threads but mine had only 1k left on warranty and I was going out of the country for a few days, so I decided to take it in and give it another try. Historically, I was told that the noise was the wastegates and that it was normal but this time, I was adamant that I was the one to induce the sound and let them take notes.

Good news... the rattle is gone! Turns out, a wiring harness above the exhaust manifolds near the left rear had a broken retainer and come loose. They fixed the retainer and wiring harness routing and all is healed.

I did not expect this, because I struggled to understand how temperature and engine load play a factor. My hypothesis is that temperature and load drive a different resonate frequency and ultimate vibration pattern that's enough to create the vibration required to strike the connector and make a noise. I didn't get good info on what exact part it was because I had to pick it up on a weekend and my tech was gone, but nonetheless, my issue is resolved.

Might be worth getting under and looking for any wiring harness connectors and inspecting their hangers. Good luck to you and the others still trying to find a fix.

Update - the noise is back and loud. I've been tapping on the resonator and think its coming from inside it. Ill have to take it back in... ugh.

 

[Jerome10]

Please keep us updated. I’m planning to take mine in once the colder weather returns.

 

[Jerome10]

Now that we're getting into the 30s in these parts, the metallic sound is really coming back again. I will need to spend some time trying to replicate consistently or locating it myself so I can point the dealer at the right spot. I basically have this winter to get this done as my 3/36 is up in May and the noise will disappear when it gets warm outside in the spring.

Thought I'd browse the interwebs and see if any new updates, I haven't found much more than plenty of folks still complaining.

With that said, and I hope the the Facebook link is acceptable, this person seems to indicate that you can somewhat easily lubricate something in the heat exchanger to eliminate the metallic/chirping noise. I don't use FB or I'd ask more questions but wanted to see what thoughts on this board might be on attempting this lubrication. I wouldn't be against it maybe, but I don't know if using something like WD-40 or high-temp lubricant would contaminate coolant or gum something else up in the system.

Otherwise still appears plenty of people complaining about this even on trucks with low miles.

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