Source Of Engine Noise/load

[alvocado]

I'm hoping to get some advice tracking down some increased engine noise and load under acceleration. For the past few months, I've experienced more noise under throttle but it lessens when I take my foot off the gas. The truck also feels like it's under a bit of load. I suspected something on the belt like a pulley since it's throttle related. The A/C compressor, water pump and belts have all been changed within the past 30k miles. The truck has 131k miles so I suspected the P/S pump pulley as a place to start. Are there any other usual suspects to check out? I'll pull the belt this weekend and spin the pulleys free to see if they are grinding. Thanks for the advice.

[MYZ-71]

may be one of your idler or belt tensioner pulleys, my 01 had a whining /whistling noise which worsened under load, turned out to be a/c tensioner pulley, I removed tensioner, removed pulley and got new bearing from local bearing shop for $18cdn.

[alvocado]

may be one of your idler or belt tensioner pulleys, my 01 had a whining /whistling noise which worsened under load, turned out to be a/c tensioner pulley, I removed tensioner, removed pulley and got new bearing from local bearing shop for $18cdn.

 

Were you able to confirm the pulley was bad by spinning it with the belt off?

[MYZ-71]

pulley had slight drag but the only way I knew for sure was too take belt off and run, noise went away.

[Grebbler]

Hard to tell without hearing it.

 

Muffler related? Fan clutch sticking?

[TwinTip]

I have the same problem on my 2003 Yukon (55k miles). I changed the belt tensioner (serpentine) this weekend along with the AC belt tensioner (AC Delco OEM parts). When I started the engine it was very quiet and I was very pleased. I went out for a ride (very slow as my kid wanted to "drive") so it was mostly idle. I could not hear any whistling but when I went out on my own and increased the rpm's to within 1,000 and 2,000 rpm's, I heard the noise again (and it drives me crazy!!!!!). So I removed the AC belt to check if the noise could be coming from the AC belt tensioner and/or compressor, the noise continued. I did not do any more tests with the belt tensioner (serpentine) as it is hard to pinpoint if this could be the source of the noise (after all, I just replaced it with a brand new OEM part).

 

Are there any other parts that could cause this noise? There is a part on the alternator that seems to have bearings but the noise seems to come from the lower right of the engine? Water pump perhaps???

 

At this time I am looking at going to the dealer as I have changed and "diagnosed" as much as I can.

 

Any suggestions???

[csheatz]

One or both of you could have expired bearings in the alternator. Like its already been said, its hard to say without hearing it!

 

Possible problem areas;

 

Any pulley or bearing,

even U joints can cause this

alternator

fan (if belt driven)

AC clutch

Power steering

And I have seen intake tubs cracked or loose where they meet the intake and causing some odd sounds.

 

hope this helps

[nubuilder]

I have a "chirp" sound in my pulley system. It seems to be a little more noticeable since I replaced my water pump and serpentine belt (I'm guessing that whatever is wearing out now has more tension on it with a new water pump and tighter belt). I can see the movable tensioner moving about an 1/8 to 1/4 of an inch (just guessing) when idling.

When I accelerate and in final overdrive, I hear a ticking sound. I always thought this was just natural from a slightly older V8 (thought it was valves or something).

Its really annoying to have someone, or especially oneself, walk by with the engine running and hearing a frickin' ticking sound from the belt system!

 

Is it safe to run the engine without any accessories (I mean ALL) not running?

How long can the battery sustain a running engine?

Or should I just revert to the tried-and-true method of wiggling pulleys with the belt and engine off?