Today I went for a lil boat ride. While going to the launch and back home, about 8 miles each way, i heard some metal to metal squeal/screeching while under hard acceleration after stops at intersections. Only did it for a second or two each time, but it happened i guess 5-6 times. Ive towed this boat many times but never did that before, but it is the first time ive towed this boat after mods. Thought i would also mention that a few weeks ago while installing my coolant filter I heard what may be the same noise. I pulled the plug on the water pump to make tie in for filter. Filled system back up with fluid. Started engine to check for leaks and heard a very distinct metal to metal squeal/screeching. But it was not sporadic, it was a constant noise. I shut engine off. I inspected everything, found nothing. Started engine again, noise again. I killed it again and called neighbor over to listen and see if we could pin point the source, wouldnt ya know it, now it stops making the noise. Although it didnt sound like a wet belt squeal, it sounded like metal, i chalked it up to wet belt that was squealing. But now this chirping while under load has got me nervous. And no its not the turbo chirping in the traditional sense, i know that sound, this is different. Thoughts? Do turbos give any notice before they give up the ghost?

Reference for what i was pulling, not your average jon boat, but its our lil piroque.

 

Have you pulled the air intake hose to check the end play in the shaft? Any smoke from the tailpipe?

 

This weekend I noticed 3 of the bolts that holds the compressor to turbine were missing! Last oil change they were there. My mechanic had this happen to his 7.3 also. He also had one split apart(stock downpipe) and was getting an exahust leak right there. 4" downpipe was probably the only thing holding ours together.

Seems to me its a pretty common issue, yet I have never read anything about this on here. Perhap your turbo split and now one of the wheels is hitting.

 

What your describing sounds more like a idler pulley bearing to me also could possibly be an alternator bearing! Turbo failures are genrraly not very loud as the rotating mass is so light it just stops quickly and boost is lost, pull off your belt and find the bad bearing before it fails completely!

 

x2 i to was thinking idler and tensioner , on my second replacements.

 

Do what Roland said first. That will take care of that on turbo. Then check idler pully and alternater. You should be able to hear them all the time with a hose to your ear and against them if they are bad. Good luck.

 

Fan clutch slipping? Just another idea. If you were pulling hard, I know its got to be hot in LA because it's HOT in TX and SC and you're in between!

 

Thanks for the suggestions guys. Ill let yall know what i find when i get a chance to check things out. Yes, its a tad warm here in LA. It will get hot come july and august. But nothing compared to central tx like you going thru. This close to the gulf the sea breezes keep us somewhat in check, but it comes at a price, the humidity is a @&#$^$.

 

To follow up on this, im pretty sure my fan clutch is going out. I read some posts where a good way to check is to spin the fan when engine is cold (after sitting overnight) and when engine is warm ( after running around). Theory was when cold the fan should spin freely with little resistence and when warm it will still spin but should have some resistence. Well, there is no difference whether warm or cold, it has resistence to spinning in either condition. Also i get the screeching noise mentioned earlier now even without towing, given our hotter temps lately of 100-105 i have noticed that when the fan kicks in is when it makes the noise. So clutch is likely going out. My question is what is the best replacement? Is there a bigger, better, badder clutch out there somewhere or does it really matter? Oreilly's list a Murray clutch for $173, a Hayden clutch for $180, and a Motorcraft for $265. OEM BABY PartsGuyEd has one for $220. Since im lookin at 2 bills either way I would go with the OEM from Ed, unless there is something bettter out there, but wouldnt neccessarily think that fan clutch would be a major aftermarket upgrade market, but who knows. So for those that have replaced their clutchs, what did you go with and what were the results?

 

I'm pretty sure OEM is the best way to go.

As a side-note, not to sing my own praises but I'm kind of proud that I correctly diagnosed this problem. Just another testament to the quality of this forum if my mechanically un-inclined self has gotten to that point. I never knew the first thing about cars and trucks until I got this truck and joined this forum.

 

Its completely different from everything suggested but u may consider this. If the turbo play is ok and you do not see any contact signs on the impeller, u may check all your boots since u describe as a screech. If there is also a clanging, then that is not it.