From what I could see happening with mine when it was making the noise, it was because that small load was just enough to cause the engine to "vibrate" a little more than at any other time when the engine is completely smooth in neutral/park or at higher rpm. Also, with the a/c compressor engaged and putting even more load on the tensioner (causing the tensioner to stay at a more "rotated" position while compressor is engaged), the sound got more noticeable.

Even at visual inspection of the tensioner with the engine off, I could tell the "floating" piece was at ever so slight of an angle to the fixed piece (no longer exactly parallel to another), like the bushing between the two was wearing thin on one side.

 

Sure. Maybe also something loose inside the wheel well? Any of the panels missing a push clip?

 

Did you figure out what the problem was??

I am really glad I found this thread. I have an 05 V6 and I know my belt tensioner is bad, because when I first start the truck up there is a bunch of noise from the fan area that gets quieter after it warms up (and my mechanic told me it was bad). So I did a search to find out how to replace the belt tensioner and found this thread...

But the really awesome thing, is that I am also having the same symptoms as mentioned in this thread... a soft grinding/vibration type noise that happens when only slightly accelerating, like 5 % throttle or less. I got the truck with 28k on it (has 63k now) and even at that time it would do it ever so often, but its getting worse now, as is the noise from the fan area.

So it sounds like replacing the belt tensioner might fix both of these issues??? That would be awesome.

Does anyone have a link on how to replace the belt tensioner? I thought I had saw a how-to post on this site before but can't seem to find it now.

 

It was a very simple job. Just remove the belt by rotating the tensioner to the stop (a Serpentine Belt Tool helps), slip the belt off, and slowly let the tensioner rotate back to the other stop.

The tensioner is held on by a single bolt, which may or may not give you problems getting it out. The head on mine sheared off after the stud seized about halfway out, which then required a Stud Extractor to finish the job.

Once the old tensioner is out, install the new one with the new bolt, and torque to 30 ft. lbs. per the manual. Ive found the easiest way to bring the belt back into the accessory drive section is to pull about half of it under the fan pulley, then with your left hand pull the belt up and over the AC compressor pulley, with your right hand pull the belt up and over the alternator pulley, then route the rest of it accordingly, leaving only the idler pulley of the tensioner unrouted. Rotate the tensioner arm to the stop, route the belt around the idler, and slowly let the tensioner rotate back after the belt is seated properly on all pulleys.

A few notes:

-Make sure not to let the tensioner snap back at any time, as damage to it could occur, and triple-check to make sure the belt is routed correctly before starting the engine. Take pictures of the belt before beginning the job if you don't have a routing diagram.
-Order a new bolt with the tensioner. Chances are, the old bolt won't be reusable. (I wouldn't reuse the old one anyway.)
-Removing the air filter box will give you more room to work when cranking on the bolt.
-You'll be working in close proximity to the AC tubing, so be very careful not to press on, or slip the wrench onto them at any time during the process. This is a simple and relatively cheap job, but as with any other minor repairs to vehicles, that could all change in an instant when carelessness and impatience set in. Take your time, work slowly.

Oh, and don't forget your favorite adult BEvERage.

 

Great, thank you. Sounds like I should be able to do this. Do you feel that an aftermarket tensioner is up to the task? I was looking at the $33 Dayco unit from Rockauto.

Do you have a PN for the tensioner bolt?

Thanks again.

 

The aftermarket tensioner I really can't tell you. The factory tensioner part number for the 2005 V6 was listed in the parts manual as 53030958AD, however it appears 53030958AE is the new replacement part which is listed in many current sources as covering the most recent models through the older ones including ours. I can only speculate it may be an improved design, and it's what I received and installed.

The bolt part number is 06504930AA.

 

Thanks for the part numbers!!

 

Just ordered the Dayco tensioner and new belt from Rockauto, came to $65 shipped. Will stop by the dealer this week to see if they have that bolt in stock.

Is there room to get some penetrating oil on the backside of the bolt on the threads in the meantime?

 

Not that I could tell.

 

Thanks guys, got the belt tensioner and belt on last weekend. It was really easy and took about 20 minutes. The silence is nice!