Whistle/squealing sound after headgaskets

[zakkb787]

As some of you know I just got the truck together in December after a long bout of issues. Since then I have this odd squeal sound. I can't tell if it's boost or throttle related. It starts around 8 psi and the harder you press the louder it gets. I tried to tighten my boost boots and things but it's still there. Could it be a loose manifold gasket or something? I tried to tighten them and they were tight as far as I could tell tho. Maybe the intake runner isn't sealed completely? Any ideas of where to start? It's getting really annoying because it's pretty dang loud.

 

[WVRigrat05]

Best thing to do is a pressure test on the CAC system, or lay under the hood and have some one build some boost and listen.

 

[zakkb787]

Best thing to do is a pressure test on the CAC system, or lay under the hood and have some one build some boost and listen.

Sounds dangerous. I like it :thumb: newbie question. What is the CAC system?

 

[WVRigrat05]

Intercooler system, pull the hot side pipe off your turbo and make a plug with an air fitting to fit in the boot and pressure up the whole system. I test mine to 30-35 psi. If you have a leak, you'll find it way before that.

I put my truck in 4x4 with the wheels chalked and have the wife build some boost, last leak I thought I had was a bad idler pulley. Mines easy and safe to do because of my big dumb bumper to stand on. First option is always better but you hear more stuff the second way.

 

[zakkb787]

Intercooler system, pull the hot side pipe off your turbo and make a plug with an air fitting to fit in the boot and pressure up the whole system. I test mine to 30-35 psi. If you have a leak, you'll find it way before that.

I put my truck in 4x4 with the wheels chalked and have the wife build some boost, last leak I thought I had was a bad idler pulley. Mines easy and safe to do because of my big dumb bumper to stand on. First option is always better but you hear more stuff the second way.

Ahh okay. What kinda plug did you make? Out of what? I'll try that first to see if it's even a boost leak

 

[Awenta]

Uppipe gasket


Sent from my iPhone using Tapatalk

 

[WVRigrat05]

Ahh okay. What kinda plug did you make? Out of what? I'll try that first to see if it's even a boost leak

I have the actual GM test plug. Most guys use a piece of pvc with a cap and drill a hole and thread a air fitting into.

But like mentioned above look for the obvious first, you'll see the soot.

 

[ChrisPerry]

I have the actual GM test plug. Most guys use a piece of pvc with a cap and drill a hole and thread a air fitting into.

But like mentioned above look for the obvious first, you'll see the soot.

Why would you look for soot coming from a boost leak? Wouldn't that only be for an exhaust leak? Curious if I'm missing something.

 

[WVRigrat05]

Why would you look for soot coming from a boost leak? Wouldn't that only be for an exhaust leak? Curious if I'm missing something.

If the uppipe is leaking there will be soot.

 

[FSUwelder1212]

You need to look for soot because the leak may not necessarily be on the induction/compressor side of the turbo. It sounds like you have a drive pressure leak, check your up pipe connections and where the manifolds mate to the heads for soot.

 

[ChrisPerry]

If the uppipe is leaking there will be soot.

You need to look for soot because the leak may not necessarily be on the induction/compressor side of the turbo. It sounds like you have a drive pressure leak, check your up pipe connections and where the manifolds mate to the heads for soot.

Ah, ok wasn't thinking about drive pressure leak. Thanks:thumb:

 

[zakkb787]

So I just tried boosting it in the driveway and I couldn't hear the sound. Got it up to about 10psi.

 

[WVRigrat05]

You're converter must be tight, I can make it to 20 in mine. Look for soot real close and then look up diy CAC pressure test.

 

[zakkb787]

You're converter must be tight, I can make it to 20 in mine. Look for soot real close and then look up diy CAC pressure test.

Well I wasn't really hammering on it. Already was trying to break loose in 4wd (gravel driveway) I looked for soot and tried to feel around and see if my hand were black but couldn't. Tomorrow after work I may go to Lowes and get a piece of pipe and cap

 

[zakkb787]

Can anyone tell me how to post a video from my phone?

 

[WVRigrat05]

Easiest to load it to YouTube and post the link.

 

[zakkb787]

https://youtu.be/qB4Xtr3Dqpo

 

[zakkb787]

Just got around to making a plug. I've got it directly on the y bridge. I can hear air escaping somewhere around the valley of the engine. Imma take a shot in the dark and assume that's not normal?

 

[TheBac]

Y bridge not seated correctly? Did you reuse the old gaskets or use new ones?

 

[zakkb787]

Y bridge not seated correctly? Did you reuse the old gaskets or use new ones?

I used new ones. But that's possible. Also could be an intake runner not 100% sealed. Or also was thinking something in the turbo. Honestly it's so close together I can't pinpoint it. I never saw any bubbles when spraying it with soapy water.