My X has been doing this for a few months, especially when very cold outside, but now its doing it even when warm so I think its getting worse. Basically when I start it up, For the first few seconds while the engine does the little rev up before slowing back down to idle, it makes a whirring/clicking noise like a belt/pulley is wobbling then getting situated then it goes away. If I start the car hot it usually doesnt do it. Last week I also noticed a tiny squeak like noise at idle for every time the serpentine belt made 1 revolution. I had them look at it when I got my oil changed but it was only doing it while cold then so they couldnt hear it, but they said my belt was looking fine. Is it a bearing on some accessory going bad? Im at 95k miles, havent done the timing belt yet. What tends to go bad around this mileage in 01 Xs (3.3 V6, auto, 4WD). Thanks

Well, as you say, you havent done the timing belt job yet,.. your at 95k, they recommend to do the change at around 105K OR seeing as the belts can suffer from dry rot Its also suggested not to let them on for over 7 years. If as you say it sounds like its coming from that area, then its not going to be a bad choice to go ahead and to the T-Belt job now. get the entire T-belt kit and you may find the problem is gone after doing the job.

I believe there's a common problem on first gens with the lifters making noise on cold startup. IIRC, it's nothing to be concerned about. Using a heavier oil could reduce or eliminate the noise. If you live in a hot climate, heavier oil would benefit your higher mileage engine

yes, the lifter noise is common, I didnt mention that since he sounded sure it was something on the front of the engine. But since it was now mentioned, along that thought, if you've had your X for a while, you should already be aware of the lifter noise situation, so just a quick note on that one, if you dont already know, make sure when buying an oil filter to get one that has the "anti-drian back" option. This will prevent all the oil from draining back into the oil pan when the engine is off, and cause oil to flow over the upper part of the engine sooner on startup. Not to push you to buy, but I have been using K&N filters, since they have that option to them. you will notice lifter noise doesnt last near as long on startup with that type of filter.