single "clunk" when starting the engine
Senior Member
Joined: Jul 2014
Posts: 411
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Pretty sure what your hearing is the blend door in the HVAC system, it's in the passenger side under the dash. I'm not entirely sure what it does, but my guess regulate air flow. My truck does it now and then.
5 Year Member
Joined: Aug 2017
Posts: 83
Likes: 18
Here is the clunk on startup of my truck
We have been hearing this too, we have about 1,500 miles on our truck, totally stock 2017 f150 4x4 f150 with EB. You can hear the clunk or more like a thunk on startup.
Junior Member
Joined: Aug 2017
Posts: 4
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From: Hillsboro, OR
I own a 2017 XLT SCAB 3.5 EB with ~950 miles on it. I noticed the same thing about a week ago. I have heard it once shortly afterward but not since. Mine was a fairly heavy thump the first time I heard it and not as loud the second time. It was as soon as the engine started.
Truck was in park with the parking break on backed into my driveway which has a small slope to it. I have been paying attention since but have not noticed it again. It sounded like it was coming from the rear and made me look in the rear view when it happened; thinking something had hit the truck. It has been warm here since then so the AC has been on every time the truck has been started. I honestly do not recall the status of the AC/heat when I initially heard the sound.
Truck was in park with the parking break on backed into my driveway which has a small slope to it. I have been paying attention since but have not noticed it again. It sounded like it was coming from the rear and made me look in the rear view when it happened; thinking something had hit the truck. It has been warm here since then so the AC has been on every time the truck has been started. I honestly do not recall the status of the AC/heat when I initially heard the sound.
Senior Member
Joined: Oct 2011
Posts: 531
Likes: 138
From: Kansas
Hello,
2017 F-150 with 3.5EB, 4x4, electronic locking diff, about 1600km only. Not too long ago I have noticed an unusual noise - a single "clunk" within a second from starting the engine. It seems to be coming from the back, although I am not sure. Does not happen every time, seem to be something like 1 out of 6-8 starts or so. I am not sure if there is a strong correlation, but it seems that it happens if I park on a slope or if I park by backing up. I do not hear that "clunk" when starting off the complete stop on the street, even if auto start/stop was on - I hear it only when restarting the engine after parking. Does not seem to matter if the engine is cold or warm, heard it in both cases.
I did some research and the only thing I have found was mentioning of a TSB 04266 (very old) and the possible need to lubricate the slip yoke.
Going to see the dealer in a couple of days but I'd be curious if anyone had a similar situation with recent F-150s.
2017 F-150 with 3.5EB, 4x4, electronic locking diff, about 1600km only. Not too long ago I have noticed an unusual noise - a single "clunk" within a second from starting the engine. It seems to be coming from the back, although I am not sure. Does not happen every time, seem to be something like 1 out of 6-8 starts or so. I am not sure if there is a strong correlation, but it seems that it happens if I park on a slope or if I park by backing up. I do not hear that "clunk" when starting off the complete stop on the street, even if auto start/stop was on - I hear it only when restarting the engine after parking. Does not seem to matter if the engine is cold or warm, heard it in both cases.
I did some research and the only thing I have found was mentioning of a TSB 04266 (very old) and the possible need to lubricate the slip yoke.
Going to see the dealer in a couple of days but I'd be curious if anyone had a similar situation with recent F-150s.
Flux Capacitor??
Thread Starter
5 Year Member
Joined: Feb 2017
Posts: 299
Likes: 54
From: Montreal, Canada
I could not hear it in the first video but this one sounds like what I have.
My dealer (Montmorency Ford in Brossard QC) does not seem to care about the customer's complaints. I am sure if I come to them with 3 wheels instead of 4, they will say that it is as designed and more than enough for the truck.
My dealer (Montmorency Ford in Brossard QC) does not seem to care about the customer's complaints. I am sure if I come to them with 3 wheels instead of 4, they will say that it is as designed and more than enough for the truck.
Last edited by ngrigoriev; Aug 14, 2017 at 09:21 PM.
Senior Member
Joined: Oct 2010
Posts: 2,723
Likes: 717
From: Crossville TN
I own a 2017 XLT SCAB 3.5 EB with ~950 miles on it. I noticed the same thing about a week ago. I have heard it once shortly afterward but not since. Mine was a fairly heavy thump the first time I heard it and not as loud the second time. It was as soon as the engine started.
Truck was in park with the parking break on backed into my driveway which has a small slope to it. I have been paying attention since but have not noticed it again. It sounded like it was coming from the rear and made me look in the rear view when it happened; thinking something had hit the truck. It has been warm here since then so the AC has been on every time the truck has been started. I honestly do not recall the status of the AC/heat when I initially heard the sound.
Truck was in park with the parking break on backed into my driveway which has a small slope to it. I have been paying attention since but have not noticed it again. It sounded like it was coming from the rear and made me look in the rear view when it happened; thinking something had hit the truck. It has been warm here since then so the AC has been on every time the truck has been started. I honestly do not recall the status of the AC/heat when I initially heard the sound.
5 Year Member
Joined: Aug 2017
Posts: 83
Likes: 18
When its loud, it sounds like it comes from the whole underside of the truck. I thought it was the exhaust banging on something when the engine shook on startup, but i have tried to move the exhaust with all my might, and no noise. Its a pretty solid thunk/clunk when its a hard one, i bet you can feel it if you had your ears covered. I have an appt on Wednesday to take it in, lets hope they can reproduce it.