Need some help diagnosing noise, lots of work done already...

[greenweenie]

Hey guys, for 10 months I've been trying to figure out what in the world is making a whining/whirring noise on my truck. I've thrown a lot of hours and money at it. I know sound is one of those things that is really tough to diagnose, and even harder over the internet, and I wouldn't be coming here if I hadn't already thrown a ton of effort at it so please bear with me. I just registered, tomorrow morning I'm going to try to capture a video of the noise and post it.

My truck is a 2015 Ram 1500, 5.7L Hemi, 116k miles. About 10 months ago I went through and did the complete 100k mile maintenance myself, including all the fluids, plugs, PCV valve, belt replacement, etc.

Preceding that, I was noticing a whirring noise under the hood when the engine was cold, and then started to hear a progressively worse howling as well. I pulled the belt, spun all the pulleys, the alternator seemed a little noisy so I replaced it. No change.

Removed the mechanical fan, installed V6 e-fan, howling gone, whirring still there.

Installed new tensioner, belt, etc. Whirring noise seems to have changed or been replaced by a different noise and is only audible to me while accelerating between 1300-2300 RPM and only happens for the first 10 minutes or so of driving. My ears detect the sound directly in front of me as if it's right in front of the steering wheel, and changes in pitch with the speed of the engine. Sounds a lot like gear/bearing/supercharger sound I've heard many describe in posts that ended up being an idler pulley.

So, like any normal human I replaced the tensioner again thinking well, that's what was changed when the noise started.... but NO CHANGE.

Replaced the water pump. No change. Replaced the idler. No change. Replaced the AC clutch. No change. I've literally replaced every single pulley on the belt drive at this point. I checked vacuum lines, generally checked everything over visually and couldn't find anything that was leaking, loose, or otherwise faulty looking. I do have the typical exhaust leak on the driver's side exhaust manifold, I have shorty headers, gaskets, and new bolts ready to go on next weekend to fix that once and for all.

I'm going to pull the idler and tensioner again this weekend and repack the bearings, maybe even though I replaced the tensioner again it's from the same lot and has a bad bearing or something. Other than that, I'm at a complete loss.

Any ideas? Or anything I should check and report back on?

I sincerely appreciate, in advance, any help received.

 

[Jeepwalker]

Wow, you've done all the items I was thinking as I was reading your description. Two things I would try are:

1) Is the fan connected to the water pump? If it is, Remove the fan entirely. Replace the bolts (washers may be needed to make up the gap). Then run it, if only for a few minutes and see if that does anything. Perhaps its part of the sound dynamics that you can't change. At least it'll remove the possibility. Or have you done this already too?

2) If you can get access to the front pulleys, if you take a wood stick or large dowel and put one end on the pully center (bolt) and the other against your ear ..you can literally hear the bearings transmit sound through the wood. Generally when a guy comes across a bad bearing, it's instantly noticeable. ...Just in case one of your repair bearings are whirring out of the box. Bearings are graded after they're made. OEM bearings are usually quite good quality. Cheaper aftermarket parts store bearings usually aren't as tight tolerance (which is why they don't usually last nearly as long). If you want OEM grade bearings you usually have to sleuth on Ebay or buy an OEM-grade part for that. I wouldn't throw away your original parts just yet.

3) Are you sure it's coming from the front of the engine? Not underneath it? Or the transmission front pump?? I know ..it's often hard to isolate certain sounds and noises. That's one benefit of removing (or disconnecting) the fan temporarily.

Other than that, I'm eager to hear other people's suggestions..

 

[Buck416]

Hey guys, for 10 months I've been trying to figure out what in the world is making a whining/whirring noise on my truck. I've thrown a lot of hours and money at it. I know sound is one of those things that is really tough to diagnose, and even harder over the internet, and I wouldn't be coming here if I hadn't already thrown a ton of effort at it so please bear with me. I just registered, tomorrow morning I'm going to try to capture a video of the noise and post it.

My truck is a 2015 Ram 1500, 5.7L Hemi, 116k miles. About 10 months ago I went through and did the complete 100k mile maintenance myself, including all the fluids, plugs, PCV valve, belt replacement, etc.

Preceding that, I was noticing a whirring noise under the hood when the engine was cold, and then started to hear a progressively worse howling as well. I pulled the belt, spun all the pulleys, the alternator seemed a little noisy so I replaced it. No change.

Removed the mechanical fan, installed V6 e-fan, howling gone, whirring still there.

Installed new tensioner, belt, etc. Whirring noise seems to have changed or been replaced by a different noise and is only audible to me while accelerating between 1300-2300 RPM and only happens for the first 10 minutes or so of driving. My ears detect the sound directly in front of me as if it's right in front of the steering wheel, and changes in pitch with the speed of the engine. Sounds a lot like gear/bearing/supercharger sound I've heard many describe in posts that ended up being an idler pulley.

So, like any normal human I replaced the tensioner again thinking well, that's what was changed when the noise started.... but NO CHANGE.

Replaced the water pump. No change. Replaced the idler. No change. Replaced the AC clutch. No change. I've literally replaced every single pulley on the belt drive at this point. I checked vacuum lines, generally checked everything over visually and couldn't find anything that was leaking, loose, or otherwise faulty looking. I do have the typical exhaust leak on the driver's side exhaust manifold, I have shorty headers, gaskets, and new bolts ready to go on next weekend to fix that once and for all.

I'm going to pull the idler and tensioner again this weekend and repack the bearings, maybe even though I replaced the tensioner again it's from the same lot and has a bad bearing or something. Other than that, I'm at a complete loss.

Any ideas? Or anything I should check and report back on?

I sincerely appreciate, in advance, any help received.

Ive had this sound myself especially when cold engine cold temps. Using a length of pipe, carefully, ear to one end other end touching moving components under hood, turned out to be the steering pump. Never did change it, worked ok just didnt like the cold.

 

[Brent 1955]

I was going to suggest that because I get the same noise in my 13 Laramie. but mine is pretty much all the time but it has been this way for 600,000 miles. When I take the belt off you can't hear the noise and nothing is lose.