Thanks duffy47, I look forward to hearing back from you. Sure sounds like we are dealing with the same noise. The water pump is high on my suspect list too.

Good luck - hopefully that's it!

 

swartlkk, thanks for the advice. I didn't know that the power steering pump pulley shaft would have some play even when new. I went to the store and had a look at a new one and sure enough it seems to have about the same fore & aft play as mine does. Mine feels a bit more difficult to turn but that may be my imagination. I am going to leave the pump alone as I want to rule out the alternator first, it sounds a bit squeaky when spun by hand. It may be nothing but at least I can have it tested. My local O Reillys autostore will do a test for free that they claim should show up any bearing problems, it sounds promising as they spin the alternator up off the truck so at least it should rule out one possible source. Will let you know how it goes.

Mick

 

Your PS pump will be a bit more difficult to turn due to being filled with power steering fluid.

 

Well, took the alternator to the shop and it failed the electrical tests on their machine. I must admit I was a bit surprised as I didn't have any charging problems that I was aware of. Replaced it with a remanufactured unit and the noise has gone! Looks like the brushes and/or bearing was failing causing the noise and electrical breakdown. Anyway, I'm happy now and recommend all with similar problems to get the alternator bench tested, its free and may just sort your problem.

Mick

 

Good deal!

 

It was not the alternator on mine. As I mentioned in my first post, I rebuilt the alternator with new bearings and brushes, and still the noise returned. I wish you the best of luck duffy47, but it would not surprise me if your noise comes back.

 

Hey, I know the K5 and the s-10 are alot different. But on my way home from alberta to ontario. about half way through the trip, this noise started and progressivly got worse n worse. It sounded like a bearing going but I just wanted to get home so i just kept goin. Well it made it home alright but still making the loud bearing noise. It cooled all night n I started it n gave it a rev in the morning and the fan shot through the hood n broke lines n the rad... I guess the bearing in the water pump went, and the shaft that goes into the waterpump(connected to the fan) was rubbing on the waterpump housing and sheared it right off. Pretty long explination and I know its alot different of an engine, but That just what happened to me.. and i was wishin i knew what it was before i wrecked my rad n tranny lines, instead of just replacing the water pump...

 

my 2004 blazer has 110k miles on it and two days ago I went to start it up and the battery just wouldn't turn it over. Since it was the original battery I though it was time to replace it. Dropped in the new battery and the engine started with no problems but the noise under the hood was bad and sounded like the noise everyone is discussing in these messages. The alternator may be a good bet since the battery was the first sign. I'll it checked out and let you know the results.

 

I have had alternators from NAPA AUTOZONE PEPBOYS you name it and my noise always comes back with-in a few months....I've learned to turn the radio up and save my parts money for a 350 swap.......and I bet it makes the same blame noisy.....

 

i have a similar issue with some form of noise under the hood. just purchased this 98 blazer for my son. i have replaced the idler pulley, tensioner pulley(not the tensioner itself though), alternator and water pump. i took the belt off and started it and the noise wasn't there. i have free movement of the power steering pump pulley with only 1 - 2 mm fore to aft "play". i have not replaced the belt 'cause it looked pretty good(no cross checking yet) also checked alignment of pulleys with straight-edge ruler. any suggestions before i look into replacing power steering pump.