Rattling

[riccbhard]

'98 Blazer LT V6 Vortec

When the RPM gets to around 1200-1600 there is a rattling that can be heard from somewhere on or in the engine. From inside with the windows up it sounds like a dull rattling and from the outside it sounds pretty much the same.

Any ideas?

[ccrtw88]

I have a 99 Blazer LT and have the same problem. I thought it might of been a lose heater shield or something but i cant find anything loose...

[corning_d3]

I've worked on a lot of those 4.3's with the same condition. The biggest part of the time, the belt stretches and causes the idler pulley to extent too far, causing it to bump itself around 1000-2000 RPM. Spending the extra money on a good quality belt will most likely rid you of this problem. Before running out and buying, though, inspect your idler pulley and mount.