I have a loud whine (more like a rattling whine) when the RPM climbs above 1200-1300 RPM. It ceases immediately when I let off the accelerator. I know it is an accessory as I ran the engine with the serpentine belt off and the noise disappeared. I feel nothing out of the ordinary when I checked the alternator pulley and the idler and tensioner, or the water pump. The power steering pulley spun fine with no apparent issues, other than it has some slight front-to-rear play (maybe a 1/6").

I do not want to change accesories uneccesarily. I tried to listen to each component but can't pin it down. Any good ideas on how best to proceed?

 

The tensioner and accessory pulleys should be replaced ~75,000 miles. If you've never performed that service and/or your truck has over that mileage, you should consider doing so. Chances are, it's the bearings in one of those.

 

My truck is just about to hit 173K. All tbe accessories and the idler and tensioner are original. I think either one is the likely culprit. They should be the less $$ to replace.

 

Wow. Finding the correct tensioner assy is a ****. Almost every one that comes up on an online search has two pulleys. The OEM on my 4.7L has only one. If anyone knows the correct P/N's for the tensioner assy and the idler pulley for a 2005 Dodge Ram 1500 Quad Cab 4x4 with a 4.7L, I'd appreciate it.

 

Here is what I found listed on Rock Auto: DAYCO 5060875K1 Serpentine Belt Kit Includes: Serpentine Belt and Tensioner

I checked e-Bay, and here are my results

My water pump failed at 120K (about one month ago). The fan clutch was bad, plus I learned when either the fan clutch or water pump fails that they should be replaced as a set. Seems when one is ready to fail the other is sure to follow. I'd already had the belt kit for my truck waiting to be installed, so the timing was perfect.

You might check the fan clutch to ensure it's not failing. The best way to do that is start the engine and idle for 15-seconds or so. If you can't see the fan from inside the cab, have an assistant watch it. Stop the engine. The fan blade should cease spinning when the engine shuts off. If it continues to spin, it's bad. If that's the case, I would recommend you replace the water pump, thermostat, and fan clutch while you're in there servicing the belt and tensioner assy.

Please follow up when you're finished.

 

Thanks. I'll look those parts up and check the fan clutch per your T/S steps. I detected nothing unusual with the fan clutch, but I did not check it as you state as I was on my own and couldn't see lol.

 

Spritz each pulley with water. The one that shuts up is the culprit.

 

Well, it does not appear to be the fan clutch. At least per the check outlined above. I started the engine, let it idle about 25-30 seconds and had my wife turn off the ignition. The fan stopped as soon as the serpentine belt ceased moving. I spun the fan afterwards and felt smooth resistance.

Back to Square One.

 

That's normal operation for the fan clutch. Yours is good.

 

At least that's one component scratched off the list of possibles. To me, the noise seems to be more on the R/H side of the engine (left looking under the hood), which should mean either the tensioner, the idler or the A/C compressor pulley. And as cycling the A/C on/off doesn't change the noise, I think that eliminates that as well.

I'll change the idler and tensioner and see what happens.