6

Vehicle:

1999 Dodge Ram 1500 Laramie SLT, with extended cab. 212k miles on the engine, all original under the hood except for a steering box and steering pump (put in in the fall of 2014). The engine is a 5.9 liter magnum v8 (360).

Problem:

A loud squeak, which I believe is coming from one of the pulley wheels. The noise begins about 10-15 minutes after starting the engine (ie, after it warms up). The squeak correlates with the engine rpms, and goes away after about 3k rpms. Also, the squeak leaves after driving through water (for a few seconds), so it's in a place where the wheels can kick water. The pitch of the squeak changes if I spin the wheel all the way over in either direction.

Questions:

  • How can I pinpoint the cause of this squeak?
  • How can I stop the squeak (if this is something I should try myself)?
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It is probably going to be one of your pulley wheels, but I doubt it's the pump. If it's brand new, they usually don't make any noise at all. It is either going to be one of either the idler or tensioner pulleys. And if you don't know which one is which, if you eliminate all of the other pulleys which have things attached to them, you should have one tensioner pulley (is a small spring loaded arm with a pulley). It may or may not have an idler pulley. If it does, it will be the other pulley not connected to anything (like the water pump or alternator, etc), but is not spring loaded (thus the name "idler" because it doesn't do anything but take up slack in the belt). If you still cannot figure it out, here are some pictures -

Tensioner pulley:

enter image description here

Idler pulley:

enter image description here

When looking at the two, don't be surprised if they both look the same (the pulleys themselves). More than likely they will actually be the same, the difference being one of them has a swing arm which is under tension, the other will just be attached to a bracket on the engine.

Like I was saying, one of the two is probably going to be bad and this is pretty normal for these pulleys. If you have 212k on the engine and have never changed either one of these, you are in pretty good shape. It should be pretty easy to tell which one is making the noise by taking the belt off then spinning the pulleys by hand ... just wing it around fast and you'll probably hear it.

To take the belt off, you'll need to take up tension on the tensioner pulley. This will allow the belt to loosen and you can pull it off. If you forget the order of how the belt goes around the pulleys, there should be a diagram inside the engine compartment (usually up by the radiator).

If you don't hear anything by the spinning/listening method, you could also possibly feel it as you turn it. It might have a bit of a scratchy feel as you turn it. You also may feel a bit of play in the wheel ... some of them have a lot of play, depending on how worn out they are.

If that doesn't get you which one it is, find yourself a mechanics stethoscope. You can pick one up at Harbor Freight for real cheap.

enter image description here

If you don't want to do that, find a very long screwdriver and place the tip of it on the pulley bolt (center of the pulley) and the handle end on your ear (while the vehicle is running with the belt in place) ... yes, if you are not careful with this method, it can be dangerous. Just remember not to have anything hanging like shirt sleeves or a tie. I usually take off rings and watch before working on vehicles ... just think safety. It should be readily apparent when you find which pulley it is, because it will be uber loud in your ear (you can also place it up to your jaw bone someplace close to your ear and you will hear it ... main point is contact with your head so the noise will transfer into your ear).

To stop the squeak temporarily, you can spray some lubricant into the bearings of the pulley. If you choose to do this, try to get as little as possible onto the belts. The best way is to ensure you utilize the little red straw which comes with the spray. I'd suggest to use WD-40, but it won't last very long (probably only a couple of hours of run time, if that). I'd use something a little heavier if available, like possibly some engine oil from a squirt can ... just don't use a lot because it will get everywhere otherwise.

To permanently stop the squeak, you'll need to replace the offending pulley. This is pretty easily accomplished by:

Idler Pulley

  1. Remove the serpentine belt
  2. Unscrew the bolt fastener in the center of the pulley (I think it's a 15mm bolt head)
  3. Place the bolt/washer into the new idler pulley.
  4. Affix the new pulley to the engine mounting bracket. (Note: Make it tight, but don't over tighten ... hard to say how tight "tight" is, though.)
  5. Replace serpentine belt

Tensioner Pulley

  1. Remove the serpentine belt
  2. Unscrew the nut fastener from the back/center of the tensioner arm (should go through the bracket and hold the tensioner in place).
  3. Pull the old tensioner from its position and replace with new tensioner.

NOTE: There should be a small dowel sticking out near the stud on the back of the tensioner. This is there to locate the tensioner in the correct position and allows the spring to build tension. Ensure this goes back into the hole in the correct position on the bracket. (You can see it in the second and third picture on this site.)

  1. Replace the nut on the back of the tensioner and tighten.
  2. Replace serpentine belt
  • Any way I could dampen the squeak before the new wheel comes? – J. Musser Feb 3 '15 at 2:17
  • Use some oil ... look above under "To stop the squeak temporarily ... " – Pᴀᴜʟsᴛᴇʀ2 Feb 3 '15 at 2:19
  • oh - sorry didn't see that. How about, as a diagnostic, spraying each wheel with lubricant, and when the squeak leaves you know you got the right one? – J. Musser Feb 3 '15 at 2:20
  • 1
    Sounds like a plan. Just don't put too much lube on there as it will get everywhere, centripetal force being what it is. – Pᴀᴜʟsᴛᴇʀ2 Feb 3 '15 at 3:12

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