Loud Squeal at start up

[Mfsr2005]

My truck has 131K miles on it. After an oil change by the dealership. I started the truck the next day and noticed a very loud squeal from the engine. It goes away after about 20 secs. But if i drive and give it a good acceleration, you hear the squeal around 3500 to 4500 RMP.

[silveradosid]

have you checked the belts, after you start it the alternator puts out a lot of power and the belt could be slipping

[Mfsr2005]

Yes, I have replaced all belts. I took it to the dealer and they said, that there is a bolt missing on exhaust manifold between Cylinder 6 and 8 that may be creating the loud whistle. Wanted to charge me between 300 and 900 depending on how they were gonna try to extract broken bolt and replace. 

[flyingfool]

i cant hear it ....

you check the tensioner?

Gates sells a belt tensioner tool on amazon,

 https://www.amazon.com/Gates-91132-Belt-Tension-Tester/dp/B000CRDLZM/ref=sr_1_16?dchild=1&keywords=belt+tensioner+tool&qid=1594996745&sr=8-16

 

hope its not something in the trans

Edited July 17, 2020 by flyingfool

[Mfsr2005]

They performed a pan drop found nothing. Did a full flush. Noise still there.

[newdude]

2 hours ago, Mfsr2005 said:

Yes, I have replaced all belts. I took it to the dealer and they said, that there is a bolt missing on exhaust manifold between Cylinder 6 and 8 that may be creating the loud whistle. Wanted to charge me between 300 and 900 depending on how they were gonna try to extract broken bolt and replace. 

 

Either its the broken manifold bolt, which is very possible, or absolute worst case, its internal.  Bent pushrod, busted valve spring, bad AFM lifter on Cyl 4 or 6.  Either way, simply changing the oil wouldn't cause this to magically start, its just coincidence.  

Edited July 17, 2020 by newdude

[Mfsr2005]

Well they said they checked but didnt believe it was any of the lifters. 

[Rukus]

Video will not play for me... however... I had what I thought was a bad belt and took it to the dealer as I replaced the belt and had same issue.  (When I started form a stop I'd get a squeak and then again at shifts).   Dealer (Bill Kay ion Lisle Illinois is horrible after 12+ years of being a customer) told me it was there flapper valve. I replaced the full exhaust system with Borla and still had squeak.   Then was pushed off due to Pandemic (understood) and then the trans would "blip" about 200 RPM when  upshifting.   Then when I down shifted I'd get a hard shift.   Took it to Chevy of Naperville and they found a bad Torque converter and the squeak was a "jet" that was restricted.   Full Tran replacement.   (Thankfully I have the extended warrantee!)

[Mfsr2005]

The sound happens when the truck is turned on. Last for about 10 - 20 sec. They it happens randomly when I accelerate. Not necessarily during shifts. Jet???

[flyingfool]

i have a bad squeek on my 2012 2500 HD , 6.0 motor and 6 speed trans. it only squeels bad when i floor it hard,  somone else mentioned it might be the torque converter making the noise, but it hasnt failed yet, and i stopped going WOT . cause i dont like pulling transmissions in the driveway 

Edited July 18, 2020 by flyingfool

[Mfsr2005]

That is the same. If i do a slow exceleration it may squeak but if i press petal to the metal it last until i let up. I guess when they dropped pan they really didn't look into the torque converter.  

[Rukus]

Yes, they said "jet" and further explained "fluid passes through there and as pressure changes the trans shift accordingly."   

[flyingfool]

i would go easy on her if you got the squeek or squeel , you might smoke the trans, it probably needs the trans pump updates , and upgraded torque converter,, put an inline filter on the cooler line and see if you catch lots of metal...

[Mfsr2005]

I will try that. I looked at the pan drop didn't see any metal in transmission. 

[flyingfool]

7 hours ago, Mfsr2005 said:

I will try that. I looked at the pan drop didn't see any metal in transmission. 

metal is usally inside the trans filter trap, cut it open and look around.  but i would check the belt tension deflection first on the main serp belt

Edited July 19, 2020 by flyingfool