Replaced both idler pulleys... noise is still there! Help!

[johnmeikle24]

Recently I noticed a repetitative whining noise emmiting from the belts on my 1998 QX4. As far as i can tell it sounds like its comming from the passenger side of the engine around the accessory idler pulley. Here's what i've done to try to fix it:

1. Assuming that it was a loose belt, I checked the tension and tightened them both slightly. This did not help. 2. Having read some other posts on this forum I noticed that the idler pulleys can be somewhat problematic. So, I replaced them both. This did not help either. 3. both drive belts were replaced when I did the timing belt at 105k (ive now got 131k) The belts appear to be in excellent condition.

My last guess is that the crankshaft pulley is going bad (harmonic balancer?). When i look at the pulley it seems to have a SLIGHT wobble (by SLIGHT i mean that it is barely noticeable, maybe 1/32 of an inch).

My questions for you all:

1. Is it common for the crankshaft pulley to have problems?2. Is a SLIGHT wobble normal? 3. Is the crankshaft pulley relatively easy to replace (i'm pretty comfortable with moderate repairs, had no trouble replacing the idler pulleys etc.)3b. What size socket goes over that outside nut? I dont have a socket large enough to fit over it so I'll have to go buy one). Does it just slide off like the idler pulleys or is there more to this job?4. Am I missing something?

Thanks for any help you may have. I'm beating my head against the hood trying to figure this out!

[timmack]

is your year using a serpentine belt or several smaller ones? im thinking that you can narrow it down by running the engine with only 1 belt on. could be a pulley on an accessory such as the a/c or alternator. if it is the crank pulley, it should still whine with no belts on.

[timmack]

oops, i guess i didnt read close enough, lol. i see you dont have a serpentine. try running the motor with no belts and see if it sounds better. if so, install the belts one at a time and see when the noise happens. that narows it down a bit.

[johnmeikle24]

Hey... thanks for the advice. Is that safe to do? I've never attempted to start the engine without the accessory belts attached. I'm a little concerned about the engine running without the water pump in operation. Perhaps this would only create a problem if the engine ran long enough to heat up. Any thoughts?

[timmack]

doesnt matter with the water pump, it runs off the crankshaft pulley so it will keep pumping. only thing that it will affect is the alternator, power steering and a/c. just dont run it real long because the battery will eventually die without a belt on the alternator. but itll be fine, you just need to let it run long enough to see if it makes the whining or not, less than a minute.

[Densetsu]

An alternative to removing all the belts is to pick up a mechanic's stethoscope and using that to pinpoint where the noise is coming from. Usually can be had for about $10-20.

Make for a good toy if you like eavesdropping as well.

[SnowSurfLax]

A good long screw driver does the trick too. And if you've already got one in your tool box, it's FREE!