Alternator Rattle..

[jstutz101]

I have a 2003 4Runner V6 with 130,000 miles. It runs fine but it makes a rattling noise when idling with either/or the ac on or the car in gear. Today I went search out the source of the noise.

With the car running and in gear (wheels chocked) I notice the rattle coming from the alternator. If I push hard on it the noise actually changes. Has anyone else had this kind of trouble?

Thanks!!

Jeff

 

[rfuree11]

My 4Runner doesn't do that, but I had a similar issue with my old Explorer. It sounds like a bearing might be going out on it.

 

[jstutz101]

My 4Runner doesn't do that, but I had a similar issue with my old Explorer. It sounds like a bearing might be going out on it.

That's what I thinking to. It takes a weird set of circumstances to make the rattle noise. If I leave the ac off put the truck in gear OR neutral - no rattle, so I think maybe its the ac. If I have the ac on and in gear - rattle BUT If I have the ac on and in park or neutral no rattle. The ac is working fine. When its rattling the alternator is definetly involved because you can touch it and feel it shaking.

Thanks for help!

 

[rfuree11]

Have you tried putting an electrical load on it (other than the interior fans) to see if that causes it? It got the the point for me that I could turn on the headlights or the radio and get it to make the noise. A reman alternator and 15 minutes and everything was solved for me. Just an fyi, mine sounded like a chattering and it was mainly when I was stopped in gear, as well. I originally thought it was the tensioner, so I swapped that and nothing changed.

 

[jstutz101]

Fixed...

Replaced the alternator today and the rattle is GONE. That was my first alternator replacement and thankfully it was pretty simple.

Thanks for the help!

Jeff

 

[cyclops13]

Have you tried putting an electrical load on it (other than the interior fans) to see if that causes it? It got the the point for me that I could turn on the headlights or the radio and get it to make the noise. A reman alternator and 15 minutes and everything was solved for me. Just an fyi, mine sounded like a chattering and it was mainly when I was stopped in gear, as well. I originally thought it was the tensioner, so I swapped that and nothing changed.

Pulling up this old thread and mine is a 3rd Gen (97 SR5), but I seem to have the exact same issue. I was noticing the rattle/clank while on idle since some time now. Yesterday evening while waiting for someone, I noticed that the noise goes away when I switch off the headlights and come back when I switch them on.

So I think its the same issue which you had noticed and assuming it would get fixed when the alternator is changed. However just wanted to get feedback if that's the real culprit. Also do I need to do this right away or can it wait till it breaks. Everything seems to be working fine and this noise is just annoying but nothing major.