Hum, Rumble on a cold 27 deg morning

[CarbonGrayFX4]

My 2022 Eco started making a rattling noise when the weather got cold (under 10 degrees F). I traced the problem to 2 metal prongs that are attached to the exhaust pipe and touch a metal support brace as it exits the engine and curves under the truck. The engine runs slightly more roughly when its that cold and causes a rattle from the 2 prongs hitting the support brace that can be heard inside the cab. I insulated the metal prongs where it hits the support brace with 2 small pieces of heater hose. That solved the rattle problem. Also, the prongs do not appear to get hot enough to melt the hose.

Are you sure the hanger didn't pop out of the rubber insulator on the support face? The two prongs are supposed to sit in the rubber cups shown above the hanger in the video below. Warning: nails on a chalk board sound:

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[jcs]

I have the same issue that you describe with my brand new hybrid. The hum noise/vibration is more noticeable when it is cold. I live in SoCal so it doesn't get too cold here but a few weeks ago we had rain and on one morning it was colder than usual and it was pretty noticeable. This noise is also present at certain engine RPMs but it is a bit hard to replicate. On that morning, when the noise was loudest, still in the garage I decided to shift it to neutral and things got wild. The gas engine started to rev up and down, rocking the truck with it and it felt as if the transmission was grabbing a gear. It also threw a CEL that lasted for a day. I took it to the dealer and showed them the video but of course they couldn't replicate. Here's the video.

 

[CajunMick]

Based on your description I think I have noticed the same noise. It seems to be RPM dependent and most noticeable at 32 deg. and below.. I notice it most at 2k. Increasing rpm seems to make the hum disappear, decreasing seems to make it lessen. I'm assuming it is just some kind of engine resonance and nothing to worry about. I bought my 2024 in October and currently sit at 11,000 miles. It runs great but is anything but quiet due to lack of sound dampening in the XLT trim.

Good info…thanks.

 

[CajunMick]

I have the same issue that you describe with my brand new hybrid. The hum noise/vibration is more noticeable when it is cold. I live in SoCal so it doesn't get too cold here but a few weeks ago we had rain and on one morning it was colder than usual and it was pretty noticeable. This noise is also present at certain engine RPMs but it is a bit hard to replicate. On that morning, when the noise was loudest, still in the garage I decided to shift it to neutral and things got wild. The gas engine started to rev up and down, rocking the truck with it and it felt as if the transmission was grabbing a gear. It also threw a CEL that lasted for a day. I took it to the dealer and showed them the video but of course they couldn't replicate. Here's the video.

Wow! That’s scary. And in the garage? See your foot on brake!!

 

[CajunMick]

Is it a Hybrid?

No.

 

[CarbonGrayFX4]

I have the same issue that you describe with my brand new hybrid. The hum noise/vibration is more noticeable when it is cold. I live in SoCal so it doesn't get too cold here but a few weeks ago we had rain and on one morning it was colder than usual and it was pretty noticeable. This noise is also present at certain engine RPMs but it is a bit hard to replicate. On that morning, when the noise was loudest, still in the garage I decided to shift it to neutral and things got wild. The gas engine started to rev up and down, rocking the truck with it and it felt as if the transmission was grabbing a gear. It also threw a CEL that lasted for a day. I took it to the dealer and showed them the video but of course they couldn't replicate. Here's the video.

I think is a totally different issue lol. Sorry about your vehicle issues though. It seems the hybrid has many more frequent issues compared to the Ecoboost. The Ecoboost is just noisey as all get out even when it is running 100% .

 

[mkrdsr1]

I think it is the AC running in Defrost mode.

 

[jcs]

I think is a totally different issue lol. Sorry about your vehicle issues though. It seems the hybrid has many more frequent issues compared to the Ecoboost. The Ecoboost is just noisey as all get out even when it is running 100% .

Ahh gotcha, I failed to see that his was an EB. I'm new to Ford and to this forum.

 

[CajunMick]

I think it is the AC running in Defrost mode.

I did not have it in defrost mode, just heater , switch w low level and upper vent outlets. I turn that off to see if any difference. None noted.

I prob wait for warmer weather, try running it, check if rumbles. Still in 30s today.

I’ll report later.

 

[d7602002]

I wish I could help. All I can say is I have an EcoBoost and we've had days where the temperatures been 15 to 20° below zero that's Fahrenheit. I have not experienced any sort of rumble or hum as you describe. I only mention that because maybe it doesn't have something to do with the cold I don't know.

 

[HeyBales]

I have the same issue that you describe with my brand new hybrid. The hum noise/vibration is more noticeable when it is cold. I live in SoCal so it doesn't get too cold here but a few weeks ago we had rain and on one morning it was colder than usual and it was pretty noticeable. This noise is also present at certain engine RPMs but it is a bit hard to replicate. On that morning, when the noise was loudest, still in the garage I decided to shift it to neutral and things got wild. The gas engine started to rev up and down, rocking the truck with it and it felt as if the transmission was grabbing a gear. It also threw a CEL that lasted for a day. I took it to the dealer and showed them the video but of course they couldn't replicate. Here's the video.

Yep, hybrid thing. Some good threads for this issue - this would be perfect addition to one to show what happens.
https://www.mavericktruckclub.com/forum/threads/2023-hybrid-xlt-cold-start-rattling-vibration.36906/
Mine goes away pretty quick by the time I'm attempting to video.
I think the engine rpm on 1st use of cool day fluctuating before it goes down to idle speed, combined with generator motor trying to do the right rpm so no pull transferred to the wheels, especially in neutral, causes it.
Or the damper between engine & transmission.

 

[CajunMick]

I wish I could help. All I can say is I have an EcoBoost and we've had days where the temperatures been 15 to 20° below zero that's Fahrenheit. I have not experienced any sort of rumble or hum as you describe. I only mention that because maybe it doesn't have something to do with the cold I don't know.

That would be my big fear, has nothing to do with cold ambient, and worry if it’s a real mechanical issue with the drivetrain. Cold ambient, IMHO, makes machinery react differently, be it tolerances, lubricants or elastomers. Recall seals on space shuttle booster rocket failed, hot flame burned thru adjoining liquid fuel tank. And experts claimed the cold cold morning it launched.

 

[Phimosis]

My 2022 Eco started making a rattling noise when the weather got cold (under 10 degrees F). I traced the problem to 2 metal prongs that are attached to the exhaust pipe and touch a metal support brace as it exits the engine and curves under the truck. The engine runs slightly more roughly when its that cold and causes a rattle from the 2 prongs hitting the support brace that can be heard inside the cab. I insulated the metal prongs where it hits the support brace with 2 small pieces of heater hose. That solved the rattle problem. Also, the prongs do not appear to get hot enough to melt the hose.

Good to know. I haven’t seen this problem in the Maverick, but a lot of cars develop a rattle in the heat shield around the catalytic converter and it is worse on cold start where the engine is programmed to high idle, the mixture is rich, the timing is retarded and the engine is running rough and loud.

 

[Jeff D.]

I remember the old v8's with cast iron exhaust manifolds. They would sometimes get a hairline crack or a stud would break or the gasket would leak. You'd start it up and it would tick, very mechanical sounding like a lifter, and as it warmed up the cast iron would swell enough the sounds would go away.

Eventually it wouldn't go away, and you'd finally figure out it wasn't a lifter after all. I seem to remember the Chevy 454 was good for that problem.

Yeah, those sounds can be real head scratcher sometimes.

 

[Timothyd]

My 2022 Eco started making a rattling noise when the weather got cold (under 10 degrees F). I traced the problem to 2 metal prongs that are attached to the exhaust pipe and touch a metal support brace as it exits the engine and curves under the truck. The engine runs slightly more roughly when its that cold and causes a rattle from the 2 prongs hitting the support brace that can be heard inside the cab. I insulated the metal prongs where it hits the support brace with 2 small pieces of heater hose. That solved the rattle problem. Also, the prongs do not appear to get hot enough to melt the hose.

A little bit of investigation sure beats running to the mechanic or the dealer!

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