Chattering/Rattling while accelerating at highway speeds

[Tally99]

Hello again -

After replacing my camshaft synchronizer twice (currently using a NAPA part), I still have a bit of a chattering/squealing/rattling noise that sounds like it's coming from under the hood. However, this noise only happens at highway speeds, and only when I put the engine under extra load, such as to accelerate above ~50mph, or when I encounter a hill.

I don't think it's the camshaft synchronizer making this noise, since I've replaced it twice now, and I was wondering if anyone had any advice on what to do to fix this. I figure it could be a bad rubber bushing somewhere, since it sounds kinda similar to the rear sway bar bushings on my old camry, and the truck is 21 years old, with a relatively unknown service history, so it might be on it's original bushings. Again, since the noise only happens when the engine is under extra load at highway speeds, I doubt it's a third bad camshaft synchronizer.

 

[Uncle Gump]

Are you certain it's not belt noise?

Are you running the A/c when it happens? If so... turn off the A/c and see if it still does it.

Sounds to me like it could be a belt tensioner/idler pulley or a worn belt.

I've never heard a bushing make a squealing noise related to engine load.

 

[Tally99]

It could be belt noise. It sounded like it was coming from the back of the engine, but my ranger is new to me, so I'm not super familiar with it.

I'll try running it without the AC to see if that makes a difference.

 

[Tally99]

Are you certain it's not belt noise?

Are you running the A/c when it happens? If so... turn off the A/c and see if it still does it.

Sounds to me like it could be a belt tensioner/idler pulley or a worn belt.

I've never heard a bushing make a squealing noise related to engine load.

It was the idler pulley rattling around, as far as I can tell. I replaced the pulley, since the old one had a good bit of bearing noise, but I think the mounting bolt/spacer/washers are worn out, since I can still feel some axial play in the pulley. Does anyone know where to get replacement hardware?

 

[Uncle Gump]

Junk yard...

 

[cbxer55]

Only time I visit a junkyard is when I'm dropping something off.