New noise

[Prairie Dog]

I have a tinny, rattling noise coming from what sounds like the clutch fan. If you ever heard the clattering that Chevy's old 6. 2 made as it idles then you have some idea of what it sounds like. I've listened to every other driven item on the front of the eng with a mechanics stethoscope and it all sounds good. There's no grinding or looseness when I turn the fan by hand. Blades have no cracks, etc.
The noise doesn't change with AC operation but does get louder at 1000 RPM's than idle. The only other change I've made is the fluid dampener but the noise doesn't seem as loud if I get me ear down toward it. The noise is very pronounced through the radiator (directly in front of the clutch) but hard to hear from above.
With as little use as it gets here in Western Wa. it's hard to imagine it's bad.
If I replace the clutch with one like this:, More Information for HAYDEN 3281 will I effectively replace everything in that assy that can make any noise?

Thanks in advance,

Scotty

 

[JFought]

check the injection tube clamps that are midway to head (usually blue plastic spacer with bolt)

#4 is notoriously known (happened to me) for loosing and making a rattle similar to what you describe. quick and easy to check them

 

[Prairie Dog]

check the injection tube clamps that are midway to head (usually blue plastic spacer with bolt)



#4 is notoriously known (happened to me) for loosing and making a rattle similar to what you describe. quick and easy to check them

Thx for the suggestion, I just did that but no change. Good suggestion though - Been meaning to do that anyway!

 

[cerberusiam]

Check the fan support bearing for noise and roughness if you haven't replaced it. You will have to pull the fan off or it is hard to tell. I chased a noise like thru the water pump, tensioner pulley until it was down to fan support of idler. Blasted clatter that was very hard to find and define. The bearing was tight with no play but when you spun with the weight off you could hear noise and feel the roughness.



If that isn't maybe chipmunks living uder the hood?

 

[Prairie Dog]

Oh man Cerb, you lost me there! "Fan support of idler"?

I thought there was just the clutch assembly behind the fan. Where is the part you speak of? This isn't like the muffler bearing is it? Still can't find that darn thing. . :{

 

[seafish]

ALSO be sure check the fan pulley/blades by wiggling them in and out (like checking the water pump bearing on a old gasser).
If the blades just barely start hitting the back of the radiator it can sound like a light rattle. That was on on an old diesel tractor of mine... replaced the water pump (which the fan was attached to) and fixed the rattle.

 

[Prairie Dog]

I tried to move the blades but the bearing seem tight and hasn't hit the radiator (yet).

 

[Alan Reagan]

Are you sure it's not the belt tensioner? That's what it was on my 05.

 

[cerberusiam]

"Fan support or idler"?

It was late and I have fat fingers. That should help.



Behind the fan pulley is the bearing I refer to.

 

[Prairie Dog]

Ah, I see. Didn't even think about that bearing back there - thx.
I'm going to take it apart today or tomorrow and see what's up.

 

[steved]

Make sure its not water pump bearings... they can make weird ticking noises.



The fan support bearings will sound loudest when standing directly in front of the radiator, with your ear about the same height as the support bearing... my dad's support bearing failed early with only about 60k, it does happen. His sounded really bad after awhile, but there was also no noteable play in the bearing either... made it difficult to diagnose. They are fairly easy to R&R.

 

[RDeFayette]

make sure the wires to the fan clutch haven't worked their way of the fan shroud retainers so the fan is nipping away at the wires.

 

[Prairie Dog]

Thanks for the replies everybody - I did use a stethoscope to listen to all the other accessories and heard no bearing noise. The fan wires are ok too.
It looks like Cerb hit it. I loosened the belt and turned the fan pulley and it seemed fine. Put the belt back under tension and turned the pan pulley (which slipped under the belt) and I could hear and feel unmistakable metal on metal grinding. Ran the eng without the fan and could clearly hear the bearing noise from the pulley. BTW, if you have a SBS then you have to remove it in order to get the fan out the bottom of the truck.
So since I had to order the bearing assembly ($142. 9you 9) anyway, I also ordered a pulley for the 6. 7 to go with my FluidMaster HB. So I should be able to find out for sure if the belt can be changed with the new pulley.

Thanks again to all who offered suggestions!

 

[cerberusiam]

So since I had to order the bearing assembly ($142. 99) anyway,

Auughh!! Send it back! That bearing is $48 delivered form Motion Industries!!!



Do NOT buy it form Cummins. If you need the number I have it somewhere. Mark Wilson looked all this up so he might chime in.

 

[Prairie Dog]

Ah crap! I should still be able to stop the order. Thx once again Cerb.

 

[mwilson]

Bearing is an NSK BD35-12AT12DDU8.



Motion Industries can order you up one.

It is identical to the Cummins bearing.



Mike.

 

[Prairie Dog]

Thanks Mike.

 

[cerberusiam]

NSK Bearing #: BD35-12AT12DDU8



Look here for a location Motion Industries - Locations





Looks like there is one in Mukilteo and Seattle.

 

[JFought]

so he is just going to replace the bearing, not the pulley or assembly, right?

 

[Prairie Dog]

so he is just going to replace the bearing, not the pulley or assembly, right?

I'm going to replace the whole cast iron assembly and while I could re-use the old pulley, I'm going to install a new one for a 6. 7.