nikolai00

Hi All,

I just starting having a belt noise that would get progressively worse once the car is driven about 20-25 miles. At cold start it is fine, but then it gets pretty bad. My 2007 RX350 has about 146,000 on it (a lot, I know) - I just replaced the belt and 3 pulleys (idler x2 and tensioner) but the noise is still there. I know I am probably due for a water pump (pretty sure it's the original) but was wondering if the symptoms of a failing water pump match what I am experiencing? (after warm-up) Could it be anything else?

Also, it's definitely more prominent when then car is in gear vs. when it is in park.

Any advice would be appreciated!

Thanks,
Nick

nikolai00

After some more close listening it really sounds like it might by the alternator decoupler pulley that makes the noise. Again, it only really becomes prevalent when the engine warms up after 20+ minutes of driving and noticeable when at a light or standing still but in gear - when parked it's there but not nearly as pronounced.

Anyway, I went ahead and ordered the second part at this link: http://www.partsgeek.com/catalog/200...er_pulley.html

I think I'll also need to pick up some special tool(s) from autozone in order to get the job done - anyone had any experience doing the decoupler pulley? I sure hope I can do it without removing the alternator itself...

DennisMik

You can "rent" tools from most auto parts stores. They take a deposit that is the price of the tool and when you return it, you get the deposit back. Essentially, they loan you the tool.

nikolai00

Yup, thanks - that's what I plan on doing!

numbafree

Maybe the accessory belt needs to be a little tighter.

nikolai00

Ok, so I went ahead and replaced the alternator decoupler pulley (ADP) with the new one at the link above. It was not the most fun job and took me about 3 hours simply because I had to fight to get clearance for the specialty tools/sockets that are needed. I could probably do this job in <1 hour next time if I had to do it again. I really wanted to avoid taking the alternator off of the car - if I knew I could do the entire alternator as easily as I could on my 05 BMW X5, then I would swap the entire assembly and not monkey just with the pulley.

Anyway, so far, so good. Drove only about 10 miles but the noise seems to be non-existent. I hope this did the trick, but at the very least I can post the DIY. The old ADP rotated kind of rough and made a slight noise when it was off the car when I rotated it, along with having a decent amount of rust/dust inside the dust cap area, so I am 90% confident this pulley was what was needed (note I already switched the 2 idler pulleys, the tensioner pulley and put on a new belt to no avail).

Tools needed:
ADP tool kit - http://www.autozone.com/test-scan-an...?checkfit=true
(rented this, and it didn't end up having the bits that I needed, so I had to purchase this one for about $30: http://www.autozone.com/test-scan-an...questid=720640)
I used a combination of these kits: the 10mm head shaft bit and the 19/17 pulley socket from the second kit, along with the 1/2" socket adapter from the first kit.
- 10mm, 12mm sockets
- long socket extension (for removing ABS module bolts)
- 10mm, 14mm, and 19mm crescent wrenches
- torque wrench

I basically followed the steps by the manufacturer on this link, except the main challenge was doing it with clearance while the alternator was still on the car (actual paper instructions included with new pulley below):
GATES: Alternator Decoupler Pulley - How to Inspect and Replace (full version) - YouTube

Here's what I did (sorry I didn't take pictures during the process - please do at your own risk)
- loosen belt from pulleys: Securely lift and support vehicle with jack stands, remove front passenger wheel, remove small panel (10mm screws), and use 14mm wrench to relieve tension and pop belt off of the tensioner pulley
- open hood, remove plastic cover on passenger side of engine (also helps to remove engine insulation cover)
- alternator pulley is right under the thick coolant hose - pop the belt off of this pulley
- pop plastic cap off of alternator (I used a small pick-like tool)
- for clearance I had to: unbolt the AC line that is mounted to the ABS module - it's 1x 10mm screw (just to be able to move the line a bit). Unbolt the ABS module (2x 12mm screws and 1x 12mm nut - use long socket extension). Unbolt washer fluid neck (1x 10mm screw)
- This allowed for just enough play for me to follow the instructions posted on the youtube link above and on the paper included with the new pulley. Be careful not to force anything you unbolted too much - gently moving them allowed enough play for me to fit the socket/specialty tool apparatus perpendicular onto the alternator shaft
- another tricky part is breaking loose the stock pulley - that thing was torqued pretty tight and at 146K miles I figured it was rusted a bit (however the alternator shaft looked clean upon inspection once the pulley was off)
- I put the new pulley back on and squeazed a torque wrench in there, torquing to 60ft-lb
- put new dust cap on - tricky to apply pressure with your fingers, especially since the new pulley is not as thick (probably about 1/3" less thick than stock), which hides the outmost face of it a bit more under the rubber coolant tube
- bolted everything back up, reseated the ABS module, AC line, and washer fluid neck
- reseat serpentine belt, and bolt back all plastic covering, reinstall wheel

Hopefully I didn't miss anything - let me know if anyone has questions. Pictures below are of the old pulley (notice the front area is pretty thick)

DennisMik

Yes, that pulley definitely was bad. Any time you have a bearing in your hand and can feel any imperfections as you turn it, the bearing is bad. If you can hear it, it is really, really bad. A good bearing will turn smoothly and effortlessly and without noise.

nikolai00

Agreed - after a few days of driving the vehicle, the noise is completely gone - that ADP was definitely shot. Thanks again.

RXGS

iTrader: (2)

Not sure if OP is still around but this was a lifesaver