This thread is related to the topic "Is anyone else's L not want to stay running on these freezing morning start-ups" except in my case the truck starts fine, its the "blowing air in coke bottle sound" that happens on first start in the morning (It's been real cold here in Athens too ;about 10 degrees. My 01 Bolt has 17,000 miles on it with no mods.
Symptons are:
1. first crank up...in about 30 seconds hear this VERY noticable coke bottle blowing sound(on mornings when the temp is below 35 degrees), sound stops after 30 seconds then continues repeatedly till engine warms up. My truck seems to bring this sound out at 900 rpm.
Took it to my local SVT dealer...thought it was the "Air Bypass Valve"...said this whistle or coke bottle sound was due to carbon being built up in the valve...said fairly common on 5.4 engines. They replaced the valve. Next morning same exact sounds...back to the dealer...the mechanic said their was a tsb out on the aircleaner not being sealed tightly in the airbox, said customers complained about a whistling sound coming from engine on first start up...mechanic took air filter out, lubed the edges with grease to help seal the air filter. Also said that you can tell if it's your airbox by beating on it while the sound is being generated; if the sound changes in pitch or level then it's the air box seal.Well, next morning (today 9 degrees),same thing.
Next step the dealer wants the truck to sit outside at the dealership all night so they can isolate the sound the
next morning. I dont want to leave my truck overnight (I'm sure you'll understand this). I really wonder about the
serpentine belt or belt tensioner...these things can make "VERY STRANGE" sounds when dirty, worn, very cold temps or defective. I even took my digital camera out early in the am (still dark)and since it does video with sound took a short video; problem was there was too many other engine noises partially masking this sound.One of us need to effectively "capture" this sound and post it on our forum. Any ideas ?
Georgia_Moon

 

Mine does it too. Ever since i went to the open air filter. Sounds kind of cool, as if he is taking a bong toke upon startup

 

yea, i think it sounds pretty cool too, but mines not loud or anything so it doesnt bother me, and it goes away, mine did it in the cold weather too

 

My brother said his alternator has been making some noise lately>??? Didn't really ask him what the noise sounded like. Maybe that is it>??? -Mat-

 

Flying **** & cpeapea - Thanks for replying.

SVT F15O - It does not sound like its coming from the alternator
area...sounds more like from the crankshaft area...but the direction of sounds can be really deceiving on an engine.
Georgia_Moon

 

Mine makes like a vacuum leak noise or whistle around 1700 rpm... And now it makes like a dry bearing noise right at start up for a couple seconds or so. Maybe that's the coke bottle noise you’re talking about. I made an appointment to take it to the dealer today...

 

I have the same sound, its especially more pronounced now in the cold. Also shows up on me when really hot (100F) out and I turn on the AC. Its only present at idle/idlish.

I'm told it is the belt tensin pulley for the supercharger. Do a search for TZRider on here, not sure if he posted it here, if not its on f-l-a-s-v-t.com on the howto about taking the pulley off, repacking the ball bearings and putting it back on.

I havn't had a chance to try it on mine.

Daniel

 

69stangscj - This sound is the same sound as if you were blowing
air into a cokebottle...not a whistling or bearing noise.

thepawn - I suspect the belt but can't prove it at this point.

 

Thats from the other board.

 

Try this tomorrow morning. After you start your truck and it starts making the coke bottle noise, squeeze the rubber intake boot and see if that stops it. There were a couple Lightnings around here that were doing the same thing and that was the cause. You may need to adjust the intake boot to get it to stop. Hope this helps...

 

thepawn - very interesting comment...excessive friction on these bearings (plus the cold) would certainly cause strange sounds...
will save your idea for a "warmer" day...thanks.

dealerjim - will try your idea in the am...never considered a loose
boot...thanks.

 

My '03 does the same thing in severely cold temps. It has only 225 miles on it. I don't think it's a terminal condition since it goes away once the engine is at operating temp. and it seems like a common complaint with these trucks. I also don't beleive it could be carbon build up causing the "air bypass valve" to malfunction since the truck is brand new.

The cold stumble is more of a concern to me since it acted like fuel starvation. Only did it once for a few miles then ran perfectly. Maybe water in the gas since I had it in a warm shop the night before for a couple of hours and then back out in the single digits (condensation?) and imediate fuel up with Sunoco 94. I usually run Mobil but this crap was on my way home.

If it continues once I break it outa the moth ***** I'll be visiting my friendly not so local SVT dealer!

FX

 

If it is the noise that I think it is , it almost fills the whole inside cab to the point where you cannot pinpoint the source of the noise. Dave at REM told me it wass the torque converter.The trans fluid get super cold and thick and it creates this sound. I tested his theory by putting the truck in neutral at a stop light(after only driving a few miles)and as soon as I put it back in drive it started to "wail' again for a second or two. I repeated this for a few more times. It seems to only occur at low rpms and only when it is cold, which tends to make me believe that he is right. Oh btw, his 500 h.p. cobra has a c-4 tranny in it and a 3200 stall converter in it and you can hear it wail from outside the car. Same sound I was getting."coke bottle " sound discribes this sound nicely! seems like quite a few Lightnings have this small problem, but he tells me its nothing to worry about.Just damn annoying!

 

Mine was emitting this particular noise in park at an idle. Other weirdass noises were coming outa the woodwork while driving 'til it cleared up. Typical hot rod... Just has to pitch a fit in the cold.

FX

 

GM: IF Mondo/Dave are correct(and if it applies to your situation), then maybe(?) changing over to Redline's D4 synthetic trans fluid is the answer? I did this about 15K ago and it was 13* this am when I left for work. My 01 L doesn't(and has never) made this noise.

Just a thought as probably none of you have tried this fluid. My tranny loves it.

Dan