Bearing Noise On Cold Engine

[ukrkoz]

Hi all

We have 99 RX300 that has rather loud bearing noise on cold start ups. It slowly goes away in about 40 seconds to a minute.

I reached as far down as I could with mechanic sthetoscope, to pin point noise origin.

It is somewhere around engine mount, maybe a bit lower. I am yet to get her up on lift, have wheel removed, and scope from the bottom.

Timing belt and WP were done around 110 000 miles. Engine has 152 000 miles on it. I don't really know, if they used aftermarket pump, most likely so.

Coolant level stays pretty solid, I may add a little bit once in a year and half. No leaks.

I am inclined to think it's water pump, as I had exactly same noise on my Silverado, then pump started leaking. But on Silvie it was roughly 30 min job to replace it. Here - you know....

Has anyone experienced this issue? There is an idler pulley inside timing cover that may go bad, but I am not aware of idler pulley bearings that will STOP making noise as they warm up.

Anyway. Thoughts appreciated.

[VBdenny]

Having just replace the idler pulley, the tensioner assembly and the serpentine belt on my Chevy truck, I know what you mean. Although I have not heard your cold start noise, I would first suspect the pulleys. If your timing belt was changed at 100 then the water pump was most likely changed as well.

Cold weather makes bearings and things make noises. I'd go down to south Florida for a few weeks and see if the noise continues.

[LEX-SV]

Temperature sensitivity and bearing noise is certainly annoying, I had it only when cold at first with idler pulley and tensioner on a 2008 Mercedes. But later it got louder and happened all the time as it started to damage the serpentine belt.

[ukrkoz]

Yes, it starts with cold noise then bearing seizes. Considering that I am likely looking at "a bearing" somewhere around timing belt, it'll tare the belt. Problem is, idler and tensioner bearings are hidden inside the timing belt cover. So to get to it, all 3 covers have to be removed.

I am really hoping it's alternator, but alternator bearing squeals all the time, not just on cold and go away.

Oh, not to forget. That noise was quite some time around. Including summer time, so trip to FL is postponed. Time wise it's the same, it is getting louder though.