Owls in the engine or hoooos making that noise?

Peteandsharon

Well-known member
We've had a few posts over time regarding funny sounds coming out of the new 6.4L Powerstroke. The turbos make a distinctive whistle which is easy to hear. However, recently I have been hearing a particular sound which sounds to me like wind howling through a crack in the window. It's just a hooooooooo sound. Like something is sucking air. It seems to happen much more before the engine is at operating temperature. It also stops when I let off the accelerator. I've checked the air intake including the air filter box to see if maybe something is not snug there. Found nothing. I haven't checked yet if it is specific to the A/C being on or something like that.

Anyway, I was just wondering if this sounds familiar to anyone. The fact that it decreases after a while concerns me a little in that maybe it could be a turbo issue. I don't know what a turbo sounds like when it's going bad but after my initial major issue with this truck, anything is possible. It's also possible it's just something as simple as the air filter box not sealing very well. The clamps are a bit loose. Anyway, any ideas would be welcome.
 

SouthernNights

Past South Carolina Chapter Leader
Pete, I think you are on the right track checking for leaks in your intake tube.

When you back off the throttle your boost from the turbo decreases so the noise would also. The fact hat it happens more before operating temp. tells you it is temp. related.

Turbos operate with VERY close tolerences. They are not very forgiving. If the bearings are going out on the turbo, it will not take long before a failure. Some real quick and easy checks:
1.) Are you begining to burn oil?? Not alot but a hint on accelaration. Check the exhaust pipe. Does the inside of the pipe seem to have a little oil in it.

2.) If you can drop the exhaust off the turbo, look inside the hot side of the turbo and look for evidence of oil. Drop the cold side and look for evidence of the turbine hitting the housing (hot side also). Of course if you see that, you probably arent running anymore.

My bet is what you suspect, a leak on the cold side.
 

BozRazor

Member
my 08 does that when it gets hot, the fan kicks in and is very intermittant, sometime when it is the hottest it dosnt come on at all, other days it cycles on at off at will, even when the truck seems like it should be cold
 

TXBobcat

Fulltime
My truck has a computer operated fan that comes on when I am pulling the trailer. Usually when climbing or taking off to get to highway speed. Blew me away the first time I heard it.. This could be what your hearing..

BC
 

Arkansas1

Past Arkansas Chapter Leaders
Hey guys,
I've encountered the same thing, but what I was told by a ford tech that operates only on fords is that ford under the dear ole guide line of the gov. had to install a waste gate at the turbo, this gate is suppose to re-burn the fuel to insure that all of the fuel is being burned, and what is happening is that when we hear the whistling and fan sound or high pitch squeal sound is that the waste gate is opening up and dumping the unburned fuel back into the turbo causing it to reburn and putting more work on the turbo thus shortening the life of the turbo, according to my tech. dude, the fix is an aftermarket turbo that has no waste gate and actually improves the fuel milage and power, at the tune of aprox. $500.00 give or take. I am currently looking into it some more! Just my two cents worth. Good luck...
Mike
 

Peteandsharon

Well-known member
Thanks guys. My sound is definitely not the fan. It's a sound that sounds like one steady note on a flute but it's definitely wind whistling through a small opening. I'm still suspicious of the air filter box since it sits on there pretty loosely. The clamps don't pull down very hard and there is definitely some play in how it fits.

As to the waste gate, I didn't think the dual turbos were wastegated. As I understand it, a wastegate is a way to bleed off excess air pressure but since the 6.4L diesel has two separate turbos, one for immediate response and a larger one for higher speeds, a wastegate is not necessary.

In any case, this sound comes at relatively low speeds, with no load and a relatively cold engine (coolant temp < 120 degrees). A wastegate would not be coming in to play here.

Thanks again for the responses, guys.
 

truknutt

Committed Member
Pete,

My '09 whistles when cold also.

Read this:

TWIN TURBOCHARGERS

Twin turbochargers! It's more than cool, it makes sense. For the new 6.4-Liter Power Stroke V-8 diesel engines, the Twins are referred to as Series Sequential Turbocharger. A low-pressure turbocharger engages at low engine speeds and load. The first-stage (low-pressure) turbocharger gets the Ford Super-Duty rolling, then hands off the baton to the high-pressure turbo charger. The high-pressure turbocharger is controlled by the Turbocharger Actuator which controls the infinitely variable vanes inside the turbine housing, from open to closed positions. An example of when the high-pressure turbocharger vanes are closed is when the outside air temperature is cold. In cold conditions, the Turbocharger Actuator will close the turbine vanes; therefore engine exhaust back pressure builds up and creates more heat, thus warming up the engine quicker. However, from the seat-of-the-pants, you will simply feel smooth throttle response and power throughout the power range. There's no waiting for the turbocharger to kick in. The Twins kick in from a dead stop right up through highway speeds; no lagging. The new turbo system can deliver up to 42 pounds of boost.

As the temps increase the vanes slowly open and you hear the whistling. My 6.0L does it, my friend's 7.3L does it. I think due to your previous noises you are more attentive to the strange sounds. Not a bad thing at all.
 

Peteandsharon

Well-known member
Thanks Truknutt. I knew that my previous 7.3 had that feature which increased the exhaust back pressure and consequently warmed the engine quicker. I didn't know that the 6.4 had the same thing. The 7.3 never made the type of sound that I am hearing now but you did know when that back pressure pressure valve released on the 7.3. All of a sudden it ran quieter. Could be that's what this is too. I'm gonna keep trying to isolate the sound. When do I hear it? When does it stop? At this point I've stopped being concerned about it. It's a curiosity more than anything. We're taking the next two weeks and pulling the Bighorn around through Wisconsin on vacation. It will give me a lot of time to play around with it. Thanks again, buddy.
 

truknutt

Committed Member
Not a problem, Pete. When I get in mine and instantly take off, it takes less than a mile and I don't hear it anymore. Of course, this is relative to the outside temps.

I'll tell you another thing; I have noticed lately (late Spring/early Summer temps) that usually my glow plug indicator only comes on for the very first startup of the day. This is when I hear the "whistle". With my 6.0, the indicator comes on every time regardless of temps.

I completely understand why you are sensitive to the different squeaks and noises given your first trip home with her!!

Now hook up that 'Horn and enjoy your trip.
 
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