Howdy guys, I am new to the forum and I am in need of some advice.

I have a 1998 C5 which I am having some problems with. It started with a grinding noise at the front end of the motor, which got worse over time.

My first thought was that the A/C compressor was going out, or rather the pulley bearings for the compressor. So I disconnected the belt that ran the A/C. Started the car and low and behold still heard the noise. Then I took of the main belt and turned each pulley my hand to see if there was any play or grinding. The only thing that made any noise at all was the water pump pulley. It was more of a rubber grinding sound then a metal grinding sound though. I went ahead and took the water pump off to get a closer look, and well, from what I can see it looks ok, but I am no expert.

Now I spoke to a tech that told me if the bearings in the water pump are going out, it would be leaking as well, and that they normally do not make a grind noise before going out.

Now here is the kicker, I put everything back on and was able to start the car without the main belt. I let it run for a few seconds and no noise was present at all. So this has to be coming from something on the front of the motor that is turned by the main belt.

Now before I go and tear the entire front half of this motor apart, I wanted to ask you guys your opinions. What should I focus my search on, and what other parts up front would make a loud grinding noise like that? And before you ask, no it is not a belt noise.

Thanks for your time.

 

I had a similar ordeal. Have you run the car and put your ear as close to each pulley that you can. I heard the grinding coming from my Tensioner pulley. I replaced with a new tensioner and belt. Also my belt was working back and forth on my idler pulley and I replaced that also. Now I have a whirring sound coming from alternator, but if I ad to gfuess my guess would be Tensioner.

 

Thank you,

You are the second person to mention the idler pulley. Yes I did get as close as I could to give it a listen, and it is coming from around that area. I will give that a look see and let ya know what I come up with.

Thanks again for your time

 

A mechanics stethoscope can help find noises like that. Or, if you're low budget you can use a piece of heater hose (but it doesn't work nearly as good). Just hold one end of the heater hose to your ear and carefully move the other end of the hose near each pulley or accessory to find which one is making the noise. The heater hose doesn't work great, but many times it works good enough to find the problem. Be careful not to get the hose caught up in the belt.

 

I checked all the pulleys, tensioner first then the idler pulleys, it ended up being the smaller of the two idler pulleys the one located near the A/c compressor. Metal shavings and grinding marks is a sure sign of something being wrong. Now here is my luck, nobody stocks the pulley I need, everyone has the larger of the two idler pulleys, I can buy those all day long for 18 bucks, however the one I needed had to be special ordered form the Chevy House for 50 bucks.

I was so wanting to get that car back on the road today Lets hope it comes in tomorrow afternoon like he said.......

Edit: Bah you know, while that pulley is bad, that is not the reason behind the noise because without the A/C belt on that pulley doesn't even turn.......I'm going to replace the two tensioner pulleys and two idler pulleys, and go from there. If the noise remains it will be time to whip out the ole listening tube