[sobieski]

Hey folks,
2004 DII 186,000 miles.
I have a pretty high pitched whine coming from the engine on cold start up (40F in Phx in Dec.).
Belt is fine.
Pulleys look ok, although they mostly from 2004.
No codes.
It almost sounds like it's coming from the SAI manifold.

Any tips on how to more narrowly diagnose, or what may be the cause is always appreciated.
Mike

 

[sobieski]

 

[reverendALC]

It’s not the SAI pump itself? The filtration mechanism is nothing more than a super cheap hunk of sparse foam which disintegrates when you look at it.

once that goes, the impeller gets dirty and can grind

 

[sobieski]

I'll take a closer look/listen and report back - thanks Rev!

 

[sobieski]

Whine noise not coming from the sai pump.
More like from the upper plenum area~ish.
I am open all ideas/theories/diagnosis.

 

[redtruck12]

I have had idler pulleys whine and that type of noise can travel and fool you as to where it’s coming from
An automotive stethoscope may help locate the source
Alternatively you can run it momentarily with the belt off to eliminate the possibility

 

[V50_M66]

My 03 D2 makes a similar noise on occasion. It's like a relatively high-pitched whining noise that comes right when starting the truck cold, then quickly fades to nothing quickly. I suspect it's the power steering pump.

 

[sobieski]

Both great recommendations.
I don’t YET have an auto stethoscope.
and i believe my power steering pump is pretty old.
thanks All.
stay tuned.

 

[sobieski]

Alternator???
More specifically, perhaps the pully on the alternator?
Anyone have any experience of an aged alternator making a whine/screech type noise on cold startup, then going away after warmed up?

 

[redtruck12]

It’s possible that a bearing is going bad. How have you determined the source?

 

[sobieski]

At cold start this a.m. whine. Rested my hand on top of the alt and sound/vibration match like a synchronized swimming team.

i know that’s not 100% but...

 

[sobieski]

I sprayed a “drop or two” of lube on that alternator pulley and the whine disappeared (this far). Note: i realized this is treating the symptom but fyi...

happy New Year!!!

 

[masantschi]

Sounds like a alternator is in your future Mike...

Happy New Year bro!

 

[discomania04]

You probably have it figure out now, but I found one of the idlers was dry and whiny. I replaced them both. Cheaper than an alternator but no sense in replacing something that's working.