engine knock or rattle, search continues... FOUND IT! Options

[malcolm2]

Let me ask......

Has anyone had an Alternator that knocks?

I have been searching for a random knocking or rattle noise. I thought for sure it was internal, maybe a rod or piston. The sound is random tho. I figured an internal noise would be timed with rotation.

Also thought it was from the passenger side.

I spent lots of time under the car with a stethoscope this weekend and I would bet a nickel it is not internal. Seems to be the fan, fan housing, or alternator; 'cause with the scope on the fan housing or alt. I can really hear the random knock. On the block, anywhere, all I hear is a faint consistent click of valves thru the case.

The fan is torqued and aligned, the belt has proper tension and the alternator was rebuilt 7,000 miles ago prior to my first start. Not sure what all the rebuild included, but I will try to find out. Thinking bearings, maybe?

I have had one suggestion.... remove the fan belt and start the car and listen. Can't think of any problems with that. Are there any?

Any thoughts or comments very much welcomed.

Clark

[Dave_Darling]

I've had one or two things fall into the fan or into the fan shroud over the years. The worst was an alternator pivot bolt that worked its way out. It was grabbed by the alternator belt and thrown across the engine bay--HARD. Lucky it missed the battery, because I'm pretty sure it would have put a hole in it.

--DD