Here's the history of this problem. I have a 1999 Chevy Silverado 1500 Z71 that I bought about 6 months ago with 112,00 miles.

I noticed a belt squeaking not long after I bought it, so I replaced the serpentine belt. No luck, still squeaking. So, I replaced the auto tensioner and the compressor belt. Still squeaking. Then, I started noticing a low moan when starting the engine and it will usually last a few minutes until the engine warms. Seems to get worse if I put in gear and hold the breaks down. After looking a little closer, I see fluid leaking from around the power steering pump. I checked the level and it was good. I assume the fluid leak is causing the belt to squeak, but what about the moaning noise. Is this a power steering pump going bad?

 

I thought I had a squeaking belt too, but to come to find out I had a dry Idler pulley and tensioner pulley. So I removed both of them, cleaned them real good with a degreaser solvent and then repacked them with grease. And of course remove the seals before cleaning and reinstalled the seals and packing them with grease. Wa-la know more squeak. So I will do my A/C tensioner pulley next... I figure since all the pulleys have the same amount of miles on them might as well grease them all, right?

 

I got under the truck last night and tried to figure out exactly where the "chirp" was coming from. Sounds a little louder around the A/C tensioner pulley, so maybe that's it. I'll replace it this weekend and see if it stops.

Still wondering about the moaning/low growl noise on start-up...I wouldn't think the tensioner pulley would cause this? Could it be the power steering pump going bad? It does NOT get worse when I turn the wheels, but does seem louder If I put the truck in drive and hold the breaks down. almost like something is getting bogged down and making the moan louder. Seems to stop after a few minutes and the engine is warmed up. Anyone out there experience this before?

 

My GMs will do this IF they are low on PS fluid, but you said the level is OK ...

 

yep, fluid level is good. I can't find anyone that has the same problem. Guess I'll replace the A/C tensioner and if it continues replace the p/s pump. If that don't fix it, I'm out of guesses

 

I have the same issue with my 89..... its just a light moan when the fluid is topped off.. gets louder as the fluid goes down.. i hear it alot when its cold outside..