I was driving today, going around a curve with a good amount of acceleration/force being put on the motor. I got a intermittent, fairly loud low whining/squealing sound coming from the engine. It stopped then came back a few times within the next mile.

I parked it at home and lifted the hood. It would intermittently start and stop and also change pitch with RMP. It seems to be coming from one of the pulleys. I don't know if a bearing went out or what...tensioners, fan, crank, power steering, alternator, water pump, idler?

So far I found a diagram of the primary and secondary drive/belts/pulleys and pumps. I guess from here I will get a piece of tubing and try to isolate where the sound is coming from exactly?

 

Listening the best I could, it sounds like it is coming from the primary tensioner pulley.

 

It's certainly not unheard of for idler pulley and tensioner pulleys to fail. I just got through replacing the timing belt on my audi because an idler pulley completely came apart and the water pump seized. My theory is that the water pump seized first which caused the timing belt to put excess force on the idler pulley and made it fail... but who knows, it could have been the other way around. Luckily, somehow, my timing belt actually stayed on and didn't skip a tooth! I love it when I actually have a little bit of luck.

At any rate, it's a personal thing, but I ALWAYS replace the tensioner when replacing belts. Not everybody does this, but I figure the tensioner is usually not too expensive and while I've got everything apart, it's a cheap price to pay for the added piece of mind. I'm not sure what the rules are on this forum for linking to other forums, so I won't include a direct link, but if you google "lr3 belt replacement", the first link is a pretty good write up on how to go about (hopefully) repairing your problem.

 

PQR500330 Serpentine belt, primary belt, lr3, 4.4l 1
PQS500221 Ac belt, range rover sport, 4.4l 2006 - 2009 1
PQG500030 Belt tensioner, serpentine belt, range rover 2006 - 2009 1
PQG500220 Belt tensioner, ac belt, range rover sport, from 7a113766 2007 - 2009 1
PQR500350 Idler pulley, lr3, 4.4l 2006 - 2009 1

 

Completed this project successfully. I was a little intimidated considering the number of items to replace, but they are all bolt on/off once you get things taken a part for the belt replacement. The link I found for 'LR3 Belt replacement' had lots of good pics and instructions for the belt replacement.

A couple of things to note.

1. The new / updated idler pulley requires you grind down a portion of the support plastic (plastic arms that radiate from the center). Grind down the area just outside the inner plastic ring. Otherwise it binds against the metal collar on the vehicle. This could be really bad if you installed/tightened it without doing it (probably have bad noises burnt plastic smell as soon as you ran the vehicle).

2. Removing the hose attached to the air intake resonator was not intuitive (at least for me). You have to squeeze the open area of the circular collar and it pops off.

3. I noted another person on that thread complained about their fan nut must not really 36mm, as the spanner slipped/stripped across the nut. This happened to me also. I figured out the rented tools spread a bit with all the abuse, so the span is more like 38-40+. I used a 5 lb hammer to pound it back into square/36mm.

 

Sorry to revive this older thread, but I'm tracing down a noise in my belts and pulleys and noted Delray's comment about modifying the updated idler pulley:

The back of the OEM pulley does have these plastic support arms, but aftermarket versions do not (see pictures). I'm assuming this mod is not necessary if choosing to use one like the Febest pulley below? And if they are being ground down anyway, are they really necessary?

OEM:


Febest:

 

Does this pulley interface with the primary serpentine belt? ....or the secondary?

 

Primary, part #7 in the diagram posted above.

 

I bought an aftermarket pulley that looks exactly like the Febest one pictured. It did not need to be ground down for installation.

 

Correct, the first aftermarket one I got required that I shave some off. Also failed prematurily. The second one fit fine as-is.