LS8 Whistle From Engine.

SoulSoak

SoulSoak

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Hey guys, just wanted some opinions on this noise I've noticed. It's a high pitched whistle coming from near the intake manifold from as much as I can tell. I had to remove the intake manifold in August when I did my cooling system overhaul. I'm hoping I didn't crack the manifold when I reinstalled it which may be the culprit of this whistle?

The car has no issues, recently put in all brand new MC coils and plugs too. Runs great, very responsive and enjoyable to drive. Just this noise is irritating me. I would think a cracked Intake Manifold would be effecting my engine and throttle response if it were truely cracked but I could easily be wrong.

This whistle goes away completely once the engine is at or over 800+ RPM. And I haven't had or noticed this noise develop until the passed month or so. (ideally the snowy weather).

Honestly though, for all I really know... I could have had this noise since I've owned the car but never really noticed it due to all the other car's issues clouding my brains focus.

Here's a quick video. Opinions/Help wanted. Worry or don't worry? Normal or not normal? Etc.

http://m.youtube.com/watch?v=jFHWHNA1DQ4


Thanks alot LVC, God Bless.
 
Nope, a small leak will only affect idle, but the larger it gets the higher the affected RPM will be because the lower the RPM, the larger percentage of air will be because of the leak. The higher the RPM, the smaller the percentage of air comes from the leak. The computer can compensate for leaks up to a point. And, Ford is known for cracking intakes.

You can try looking for the leak several different ways. If nothing is obviously disconnected like a broken vacuum line, you can use a heater hose against the ear to try and localize the sound. You can also use a propane torch, turn the gas on but don't light then run the tip along the intake until the RPMs jump.

When you reinstalled after the coolant job, did you follow the bolt tightening sequence exactly, and do it in stages? And, did you replace the gaskets? The tightening sequence must be followed exactly or you can warp or crack the manifold, and the crack/warp might not actually happen until the engine has been cycled several times.
 
Telco said:
Nope, a small leak will only affect idle, but the larger it gets the higher the affected RPM will be because the lower the RPM, the larger percentage of air will be because of the leak. The higher the RPM, the smaller the percentage of air comes from the leak. The computer can compensate for leaks up to a point. And, Ford is known for cracking intakes.

You can try looking for the leak several different ways. If nothing is obviously disconnected like a broken vacuum line, you can use a heater hose against the ear to try and localize the sound. You can also use a propane torch, turn the gas on but don't light then run the tip along the intake until the RPMs jump.

When you reinstalled after the coolant job, did you follow the bolt tightening sequence exactly, and do it in stages? And, did you replace the gaskets? The tightening sequence must be followed exactly or you can warp or crack the manifold, and the crack/warp might not actually happen until the engine has been cycled several times.
Click to expand...

Yeah... I didn't follow the procedure to properly torqueing down the Intake Manifold when I reinstalled it. I did notice however, that after I inquired about the procedure, the way I torqued my manifold down was very similar. Granted, I know it's supposed to be done via the procedure but I doubt that the way I did it is the cause for this noise. But I suppose I don't doubt it as much as I do doubt it lol.

Fuhhhhh. It would make sense that maybe I have a leak from the manifold, just wish it wasn't the case. And yes I installed new gaskets as well. I suppose I could break all the bolts loose and retorque the manifold down to spec and in the sequence it's called for. Just somewhat afraid that I could make a not so terrible crack/leak turn into a major crack/leak and be imobile until I get a new manifold.

Atleast they're cheap right? lol.
 
Let us know how your troubleshooting goes. Pretty sure I have a vacuum leak around there somewhere as well. Tried puffing smoke around the manifold but it didn't work, only ended up stinking up the cabin because I forgot to turn the HVAC off. :Bang
 
M4rk said:
Let us know how your troubleshooting goes. Pretty sure I have a vacuum leak around there somewhere as well. Tried puffing smoke around the manifold but it didn't work, only ended up stinking up the cabin because I forgot to turn the HVAC off. :Bang
Click to expand...

Will do. First thing I'll do is spray some starter fluid around the manifold to see if the rpm's jump. If the rpm's remain unaffected, I'll further inspect vacuum lines. Then finally, I'll break the manifold bolts loose and retorque them to proper torque and in correct sequence. Shouldn't be a problem, the manifold bolts are easy to access that I recall. Removing the manifold however is a whole other story lol. Going to do this tomorrow after work.
 
I have had the same whistle since I owned the car. No issues and it has stayed the same volume over these 4 years.
 
I think the manifold is a couple hundred bucks. And, if you can hear the whistle you should be able to close in on it with the heater hose to the ear. I'd do that before cracking the manifold open again, just in case that isn't it.
 
Andrizzle said:
I have had the same whistle since I owned the car. No issues and it has stayed the same volume over these 4 years.
Click to expand...

Yeah I found your post from '09. You mentioned the annoying whistle you suffered through while trying to bleed your cooling system after a new degas install lol. Never found the culprit though so I made a new thread.
 
Telco said:
I think the manifold is a couple hundred bucks. And, if you can hear the whistle you should be able to close in on it with the heater hose to the ear. I'd do that before cracking the manifold open again, just in case that isn't it.
Click to expand...

Yeah I think I'll do further inspection and I probably won't break the bolts loose to retorque the manifold yet. Simply because I have no real problems, so why create some lol. If I start having problems then I'll find me a new manifold, then attempt to retorque the current one while I have a backup handy.

Thanks guys, I'll keep you posted. However we just got a good snowfall here in Michigan so it won't be today.

God Bless
 
Tbh... I'm beginning to think that the whistle is kind of cool. I mean, it may be a combination of the thought of trying to locate the source of the sound as well as the insanely high price for a new manifold. But I think I'll just look at it this way... "My car can whistle, yours can't". Deuces!!
 
Hey Soulsoak, in second #10 of your video it shows a little red tube under wire duct. It's a little hard to see due to the speed of the camera, but that little red tube isn't crushed is it?
 
Telco said:
Hey Soulsoak, in second #10 of your video it shows a little red tube under wire duct. It's a little hard to see due to the speed of the camera, but that little red tube isn't crushed is it?
Click to expand...

I'll take a look at this tomorrow and get back with you. Why the inquiry?
 
Okay it was bothering me so I looked. The only red tube I seen was two separate red tubes running from my EGR valve to my Throttle Body. They run together parallel inside black wire loom, and no they aren't pinched. Thanks Telco
 
Since it looked pinched, and looked like it was where other vacuum lines were, it looked like a possible cracked hard plastic line which would whistle when it leaks. And, before anyone says it, I don't know what the vacuum lines on top of the engine look like. I've only had my engine cover off once for the coolant system job last year and I don't remember the specifics.
 
There's a thread here somewhere where I got an EGR related code which turned out to be cracked/broken hard vacuum lines. I broke a couple moving them around when I cleaned the TB.
 
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