Timing idler pully bearing flew apart going 70.replaced itand timing beltbut it still acts like the timing is off.

COULD BE A BAD BEARING IN THE IDLER PULLY OR THE TENSIONER ON THE TIMING BELT OR THE SERPENTINE BELT. IF ITS A SQUEEL IT MAY BE SOME COOLANT GOT ON THE SERPENTINE BELT. TRY TO WASH THE BELT WITH WATER AND LET DRY COMPLETELY. IF NOISE REMAINS RETURN TO THE SHOP THAT DID THE WORK.

Being it's 92 model i would replace them. The pulleys may appear to spin freely until the belt tension is applied.

Just an idler, probably has a frozen bearing, you will need to get it repaired.

Carefully check the condition of the belt, the tensioner, and the idler pulley. I had the same thing happen and once I knew where to look, I could see that my idler pulley bearings were bad (understatement...they were GONE!)

Your idler pulley and tensioner need to look even and straight and not leaning in or out. A sure sign of a problem is if one or the other leans in toward where the tension from the belt would be on it.

The best way to check is to buy, rent, or borrow a serpentine belt wrench to take the pressure off and then try and wiggle the tension and idler pulley. If you feel any play, replace as soon as possible. I dragged my feet and ten days after I heard the noise, my idler pulley flew apart right as I pulled into work.

Sounds like your drive belt is slipping, it is either worn out or needs adjusting. You may near it louder when turn your steering wheel.

THAT sounds like a bearing in either /Alternator/belt
idler/water pump/or powered steering.
You say when it get to 70 but what is the rpm not speed as all pullys are differant sizes so rotate differant speeds OR check the power steering belt and others for cracks or loose.

Could be several things. WHICH ENGINE?.. 4 cylinder (has three belts, power steering/water pump, alternator & A/C compressor, one tensioner pully A/C compressor), The V6 2.7 (has only one belt, 1 Idler pully and 1 tensioner pully), the V6 3.5 has two belts - A/C/alternator, and power steering - there are two tensioner pullys). Noises can be caused by the belt(s) themselves, pullys, bearings, pully bearings, water pump shaft bearings (or belts/pullys rubbing up against something). Let's not forget that there is also belt(s) behind the Timing Belt cover as well as pullys and bearings associated with the timing system. You could start by removing one accy drive belt at a time (alternator, water pump, compressor, power steering, etc) to see whether or not the noise goes away in each case. If after each case, you discover the noise is still there, it's probably behind the timing belt cover (idler/tensioner pully, water pump shaft bearing, crankshaft bearing, etc.). Good Luck

check the idler/tensioner pully's and the alternator pully, there is a common problem with one of these 3 going bad, usually an idler pully the best way to check is to get a mechanics stethescope and touch the end to the bolt on the idler pully's you will notice a very distinct sound difference from a smooth pully and one with bad bearings. gm tech here, seen many of these

Bad bearing on idler pully? Replace pully.  

how many km or miles on it if over 140 000km then should be needing an alternator the brushes should be down to springs .and the bearing could of been out of the idler pulley back side