Odd Sound

[Cary and Don]

It's a 6v92 with blower and turbo.  There seems to be a high pitched sound, kind of like a bearing sound, in the engine compartment.  This seems to be the most evident when first starting up.  It is so slight, that we can barley hear it.  Can't tell if it is the blower, turbo, fan, our imagination, or something else.  Any ideas?

Don and Cary
GMC4107
Neoplan AN340

[bobofthenorth]

Belt squeal?  If its most noticeable at startup that would be my first suspicion.  A worn belt can be tight and still slip.  Try some belt dressing rather than tightening.

[TomC]

Typically, if you're hearing a bearing noise, it would be from the blower since it has ball bearings.  Whereas the turbo has slipper bearings.  Also, alternator, power steering can make noise at start up also.  Bearings can make noise for years and not mean a thing, or they can drop out without warning-never know.  Good Luck, TomC

[Dreamscape]

Typically, if you're hearing a bearing noise, it would be from the blower since it has ball bearings.  Whereas the turbo has slipper bearings.  Also, alternator, power steering can make noise at start up also.  Bearings can make noise for years and not mean a thing, or they can drop out without warning-never know.  Good Luck, TomC

Sorry Tom, I must respectfully disagree. When you hear a bearing, you can count on failure. It means there is a bad race or bearings themselves, or it could mean bad alignment somewhere. A bearing should not make any squealing noise with the proper lubrication. I have installed hundreds of them and if I hear one making an unusual noise, I better go find a replacement and schedule downtime to fix it.

Paul

[boogiethecat]

Alternators often create a whine just after starting up because the battery is low and they are working their hardest at that point to restore the charge. And the sound tapers off quickly as time goes on, 'cause most of the charge is replaced fairly rapidly.  So if it's not a bearing whine, it could be the alternator, and it'd be normal.  More often you'll hear it in your stereo though, as the electrical noise it generates is usually more noticable than the mechanical noise it makes. But I've heard both...

[busshawg]

for some reason I doubt it's a bearing, too many other things as opposed to a bearing back there. I do agree that when you do hear a bearing squealing it is best to find it and get it changed out a quick as possible. Does it consistantly go away as it warms up? does it go away completely?

Grant

[johns4104s]

Harbor freight has inexpensive stethoscopes, I would start there and check around till I can find it.

John

[WVA_NATIVE]

I heard about a guy who started his car one time and started off down the road but as he drove he heard a squeal come from the engine. If he drove faster it got louder and when he slowed down it would get quieter, so he pulled over and got out opened the hood and there was his cat clinging to his carburetor cover. He said the cat had a wild look in its eyes and he had to pry the cat off the carb because it was hanging on for dear life.

So I know its a diesel but you still might want to make sure you have accounted for all your cats. LOL

[Cary and Don]

Did the cat thing once already.  It was sleeping on the warm engine overnight.  It was a real shock when the engine started.  It ripped the throttle linkage loose on the way out. Luckily, the cat missed the fan.
Sound isn't the power steering, it squalls real loud on starting if it is a little low.  Our worry is it could be in the blower, the one extra part we don't have.  Not a belt.  The compressor sounds like a thrashing machine, but don't think it can squeal.  It does go away once warm, and it is so faint when cold.  Just don't want the blower to end up in the engine.

Don and Cary
GMC4107
Neoplan AN340

[Ed Hackenbruch]

If you have the $$$$, you could always buy one and put it on and see if the noise stops. If it does, fine, you fixed the problem before it got worse.  If it doesn't stop the noise, well, now you have a new blower on and an older spare.