screach at 4k rpm
 

ok, got tired of waiting for my 45dcoe from RS, so i put the original carb that stopped working back on to see if i could get it to work (i rebuildt another but it was leaking bad). aout 15 min. later the car was good and idleing at about 1k.
so onto the screach, at just over 4k it makes a godawful high pitch screach, its not to noticable after awhile it blends in witht he exauhst leak when driving.
Figured it was a loose alternator belt, so I tightened it, still did it; So i got my dad out there and he says it sounds like a bearing, so in hopes of an easy fix i went in the garage and got a spare alternator, still made the damn screach;
my dads only other thought was it could be a water pump bearing.
Has anyone had this problem (im serioly hoping its not an internal bearing that is goin) and what was it?

thanks for any input on my noise

anything?

It does sound like a bearing... clutch, maybe? Does it smell? Does it only happen when driving, or will it also screech if you rev it up while stationary?

You didn't tell us much about your car, but if it's an SE or a GSL with power steering, I had a similar screech at higher rpm when the PSP idler bearing went out. This causes the screech that never ends, and a little wd40 on the bearing (idler pulley) seemed to fix it until I could get the right bearing from the Mazda dealer and pound it out.

First thing to do would be to get a can of 3-in-1 oil and try dripping that down the front cover onto the eccentric shaft (mail pulley bearing), the airpump pulley, and anything else that may have a bearing on the front of the engine. Check for the noise in between to figure out which component is causing the problem.

This could also be as simple as belt slippage under high rpm, so check all the belts and make sure that they're not greasy on the underside, or otherwise induced to slip. Good luck,

I have the same thing on my 85 GS. Check the alternator again. Check to see that the alternator pulley is directly in line with the drive pulley. It will be apparent if you look past the belt and pulleys and just see them in your peripheral. Also look right where the belt start to contact the pulley, it will bend slightly.

My alternator is sitting about 1/4" out of line and has the exact symptoms. I need to get some washers to realign it.