Thread: rattle at idle

My wife's 2000 GT (non turbo) has a rattle at idle and it appears to come from the tensioner pully. I used a stethascope (sp) to find the location of the noise. I've replace the pully, but the rattle didn't go away. Does anyone have a suggestion of what to do next?

Try removing the belt and spinning/wiggling all the pullies by hand and see what rattles. You may find that the alt. is rattling causing the sound to resonate down into the bracket, which is where the tensioner lives. Could also be a waterpump.

Worse case scenario you could start it with the belt off for a BRIEF moment and see if the rattle disappears. If it doesn't then you're rattle is something in the motor that is not turned by the belt (ie- lifter, rocker, etc...).

Thanks for the replies. I did try it without the belt and didn't hear the noise, but I can hear a squeal from the alternator when the temp is cold and the engine first starts. All of the bearings turn smoothly. The tensioner appears to have good tension and isn't loose.

I'll pull the alternator apart to see if I can find a bad bearing.

Problem solved! The belt tensioner was the problem. I used a Gates tensioner and it was exactly the same as the original one. It even was made by the same company in Canada.