hissing coming from behind the dash, most likely from turbos

[salt_life_87]

Driving to work this morning and as I am passing a slower vehicle 75% throttle from 55 to 70ish no radio on I start hearing this hissing noise coming from behind the dash. Pretty noticeable, I couldn't identify it yet because it's still dark but I'm think the vanes in the VGT turbo stuck. Boost is down by 1 psi. My scan Guage II reads 21.3 psi normally it reads 22.4 psi. No CELs

I just had the turbo feed line fixed as it lost the main bolt to the block so it spewed oil and the up pipes were just replaced. I think once I fix the issue big Bertha is getting traded in. Love the truck but I'm done with headaches which are now back to back.

Do the turbos make a destinctive sound when the VGT messes up? Acceleration is still normal and doesn't skip anywhere.

 

[sootie]

loose or cracked uppipe would be my guess. check for split or loose intercooler boots also

 

[salt_life_87]

Yeah I was thinking exhaust as well, up pipes from Rudy's are new and the cross over from the passenger side up pipe to the driver side EGR cooler was bought used.

If it is I'm gonna charge it to the game, that's another 1100 at least to get it fixed. The first leaks didn't start off like this one but it was only the bellows. If the pipe is cracked I'd imagine the same laggy turbo and pickup.

FML!

 

[Jbird]

I have this problem. Mines more of screeching or squealing noise but very noticeable. I pull the same amount of boost as always though. If not a little more


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[salt_life_87]

Have you had it diagnosed jbird?

Mine is all stock at 99k miles with just the airaid intake that came on the truck, 2008.

 

[Jbird]

Nope just started happening. A week or two ago


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[salt_life_87]

So I tore down all the heat shielding from above the turbos as it was saturated in oil from the turbo feed line issue I had a week ago.

Well after some burnt skin and what felt like a long drive home hearing straight hissing the whole way. Turned out to be a spot on the back side of the driver side turbo leaking air. It's right around one of the bolts that is blocked by the cross over pipe but the shop just installed the new up pipes and I'm sure they'll do right by me and fix the issue. I'm saying that in hopes that the pipe doesn't have a hole and needs to be removed and welded up.

Damn up pipes.

 

[salt_life_87]

So like an idiot I used the wale designed style gaskets when they replaced the pipes and didn't buy new Ford ones and the dam gasket that came with the up pipes blew on the driver side turno.

Couple of hours of labor to replace that 1 gasket and the pssenger side if it goes is going to be just as long if not longer to get to so I'm thinking of having them do both sides just to not have to deal with it again.

Another 300 bucks down the drain on a damn 10 dollar gasket. Bad on my part for being cheap I guess.

 

[Layson]

I just had a friend complaining about a whining under boost on his 6.4. I got under the hood and his clamps on his boots were not tight enough. I was thinking uppipes or something more complicated then his clamps not being tight enough. Went for a drive after we snugged them up and no more noise. For once it was something simple...LOL

 

[Jbird]

How can u tell if its the gasket


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[salt_life_87]

He showed me the gasket, same one from Rudy's diesel a generic type waffle texture vs the factory ford all metal gasket. All burnt up and barely anything there, just detoriated from the heat.

I also pin pointed the leak from the turbo to up pipe before I dropped it off.

 

[Jbird]

I was just trying to figure out how you pin pointed. Was it leaking enough at idle for you to find? Soapy water?


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[salt_life_87]

Yeah, at idle it was pushing through and with boost the hissing got louder at idle it was a slight his. Considering I just had the pipes replaced and the issues I've been having have been in the turbo area I looked there first.

I just put my hand around the turbos feeling for it

 

[Jbird]

Ok im gona check mine out. I cant hear mine at all unless im in the throttle


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[Jbird]

So mines been down the last few days waiting on a coolant hose that was leaking. Got that all put together and drove it last night and this morning to work. The screeching hissing noise seems to only happen when the trucks in 3 or 5th and between 2100-2700 rpms. It doesnt really change with the boost which makes me wonder if its not something else. Ive noticed the truck feeling laggy for the amount of boost it has. Rolling 20-30 psi and still feeling like it doesnt want to go. But that might be the tuning. I dont know where to start looking for this


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[6.0 Tech]

So mines been down the last few days waiting on a coolant hose that was leaking. Got that all put together and drove it last night and this morning to work. The screeching hissing noise seems to only happen when the trucks in 3 or 5th and between 2100-2700 rpms. It doesnt really change with the boost which makes me wonder if its not something else. Ive noticed the truck feeling laggy for the amount of boost it has. Rolling 20-30 psi and still feeling like it doesnt want to go. But that might be the tuning. I dont know where to start looking for this


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Check the exaust manifolds for broken bolts or soot blown all over.

 

[Jbird]

Have you personally seem this? Jw if the head of the bolt breaks or if the thread itself breaks off flush with the block


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[6.0 Tech]

Yeah, ive seen a bunch. Most times the bolt breaks flush, if not almost flush with the surface of the head. Its damn nearimpossible to drill them too because all the heat cycles harden the bolt.

 

[Jbird]

Is there enough room to work with it under there with the cab down


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[benjamindurtka]

I had that bad hissing on drivers side this morning. Pulled over to check the connections and see if I could feel any obvious leaks or see any soot anywhere...
Was pretty bad when I first left the house maybe 3 miles before I pulled over. Stopped when I parked and hasn't happened again. Thinking maybe the ebpv was stuck closed? I will be doing a leak check as soon as I can from the intake.

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