derekmj64

On my trip back from up north this weekend my turbos on my truck all of a sudden changed tone at WOT. I was pulling a pretty decent weight trailer when I accelerated hard to get on the expressway I noticed a new sound which resembled a really high pitch whistle/in rush of air. It still consistently happens now even without the trailer but only at WOT throttle from roughly 3,000-4,500 RPM. Once I got to around 4,500 the sound would cut out. It is way louder and a different pitch than the normal turbo sound (I've owned the truck since new and this is the first time I have heard it). It almost reminds me of my buddy's truck with a cold air intake just the pitch is higher (my truck/intake is stock).

I tried to get a video of the sound last night using my GoPro in a couple spots but every time there was too much noise from the wind. I am going to try to get my wife to video me doing a drive by to see if that will better capture the sound. I did check some of the top intake clamps and vacuum lines and they seemed to be tight and good condition. I wonder if there could be a line off somewhere that I am missing or if the flex joint at the resonator could be going in my stock exhaust. Just not sure where to go from here and if any of you have had a similar situation (I know that it is hard to accurately describe a sound). There is no loss of power and still building 12-15 psi of boost.

Here is a link to the best video I took last night. (the sound starts around 3 seconds and cuts out around 5 - very short window).

I was wondering if it could be related to the following TSB 15-0071:
https://static.nhtsa.gov/odi/tsbs/20...58057-1185.pdf

Truck info:
2013 3.5L Ecoboost F150 FX4
91,000 miles

I appreciate the help!

HuntersSenseTV

Can you hear the BOV (Blow off valve) when you release the throttle? I only ask because i did the VTA mod on my blow off and it made the turbos sound louder when they were spooling. Check the BOV, located on the back side of your intercooler, looks like a small black canister. There is a hose that should run from the back of the BOV up to the intake so make sure that it is connected.

derekmj64

I did not check that but I will tonight. Thank you!

derekmj64

I replaced by BOV (both manifolds and gaskets have been replaced within the last year) and I am still getting the noise consistently under moderate to heavy acceleration in the same 3,000-4,500 RPM range. I tried placing my GoPro under the hood to see if I could detect abnormal turbo noise or a boost leak. I was unable to hear the actual noise in those videos but I could hear it when I placed the GoPro under the truck at the resonator/flex pipe. I am wondering if anyone else has had their resonator or flex pip go out a make a hissing sound (also sounds similar to spinning a dry dirty bearing) under boost?

My truck still is building 15psi of boost but does feel like it's down a little on power and fuel economy (this part could all be in my head though )

Truck Info Again:
2013 F150 FX4 EcoBoost - 97,000 miles.

Noise happens between 22-25 second mark in the following link:

av8torken

Kind-of sounds like the dreaded warped exhaust manifold issue, which I also have. Only one way to permanently fix it is to use CRP manifolds. Putting OEM ones in will eventually be warped again (may not matter if you get rid of truck eventually).

derekmj64

Both manifolds, studs and gaskets are no more than 18 months old.

av8torken

Ford ones though? If so, the quality is not that good on them compared to the heavy walled CRP. I've yet to do mine because I'm going to do several engine related things all at once (timing chain, etc)

derekmj64

Yes they are the factory Ford maifolds and gaskets. They were replaced by the dealer through my extended warranty. I figured that the factory ones got me to ~85,000 miles so by time these go again it will be someone else issue.

av8torken

I would check/replace if necessary the downpipe to turbo gasket on driver and passenger side.