this 95 850 developed a high pitch squeal in the serp belt area so, replaced belt with new length and re route. the re route throws the belt off the alt to the outside. figure, the idler is worn out and the new routing with the distance from over the p/s around the idler throws the belt off . today, replace the idler and the belt is thrown off instantly. now , given what a pain that new routing is, and a new idler pulley in place I put the old belt/routing back on and am driving. I have no alt belt contact problems. can I get old route belts anymore? why is this happening?

 

Your routing is wrong, or something is not aligned correctly (compressor, alt...)
what type of belt did you get?
Some of the cheaper belts have the wrong routing on the sleeve.

You can get the older belt by number but it may have to be ordered.

Here is the new routing from vadis.

 

Well, the noise was not the idler. But the new belt is a conti and routed exactly as in the picture,(what a pita). After looking around this forum in the search mode this whistling sound seems common but this car is not a turbo. The whistling/whirring sound does not increase in pitch with rpm's, the noise increases in volume, that is it gets louder.So do we have a vacuum leak here? This thing is driving me nuts .thanks

 

So the belt is not popping off anymore?

The whistling could be a vacuum leak easily, does it increase in park by just raising the rpm's?
If so it should be fairly simple to pinpoint the area of the sound.
If its on the belt side have you checked to see if its coming from inside the timing cover area it could be a tension er in there or a bearing.

But I would check ALL of your vacuum lines and fittings first.

 

Check your a/c, p/s, alternator and intermediate pulleys too.
Spin them and listen.
Ed

 

Thanks,Guys. I am still running the old routing with the short belt and it stays on. The new belt and routing is what gave me the throw-off problem, with the belt going all the way around the idler before reaching the alternator, thus my suspicion about the idler pulley. Now, yesterday I got a better listen and it seems like it maybe the alt. but wouldn't the pitch (frequency) increase with rpms? And, could this be related to a PCV issue, as I have some smoke at the dipstick and oil on top of the engine (all the regular symptoms.) Today I'll check under the T belt cover. I really appreciate the help, Guys. This car is my daily, so I can't wait for it to just break and pick up the pieces.