Metal Rattling Noise at Initial Acceleration ....

[BGBronco]

76. 302. C4

I am getting a metal rattling noise on acceleration that I can't narrow down.

It occurs under initial acceleration and then stops when I accelerate through it. It only happens from dead stop under moderate acceleration. It is definitely acceleration related. However, I can use the accelerator to keep the rattling noise going.

I've tried to see if there is anything loose on the tranny and related areas but everything seems tight.

Thoughts?

 

[BGBronco]

Further investigation ... seems like it's the fan hitting either the shroud or radiator.

 

[B RON CO]

Hi, you may need new motor mounts.
Try jacking up the engine to see if the motor mounts are loose.
Good luck

 

[SHX669]

Hmm - metal rattling in a Bronco - lets start at # 100 and work down - LOL
How bout the muffler/exhaust pipes and the mounting brackets.

 

[spap]

Did it start all of a sudden
Is it like a scrapping rattling noise
Does it change with rpm
Does it happen when you reve the engine in park or just when driving

 

[spap]

Haaa lets start at 100 is classic, do you own a bronco yes, does it make a rattling noise yes haaa

 

[73azbronco]

Is it preignition/knocking noise?

 

[BGBronco]

My radiator is a little loose so I'm going to start with that and work my way to the engine mounts. It doesn't seem like the mounts will be a big issue based on what I've read but it's a little out of my wheelhouse.

 

[SteveL]

Is it preignition/knocking noise?

This was my first thought. Also mufflers and cats rattle when the guts come loose but its usually more noticeable at idle.

 

[Broncobowsher]

Is it preignition/knocking noise?

My first thought as well, as the seasonal fuel blends changes and the temps start to rise.

 

[AC932]

Any bottlecaps in your ashtray?

 

[Rustytruck]

Check the backlash in the timing chain. They can rub the timing cover when excessively loose.

 

[73azbronco]

Any bottlecaps in your ashtray?

This shows true Graduate Level EB ownership right here ladies and gents.

 

[BGBronco]

Any bottlecaps in your ashtray?

That's pretty funny.

 

[blubuckaroo]

Further investigation ... seems like it's the fan hitting either the shroud or radiator.

Yes, noises like that can happen suddenly!

 

[WheelHorse]

What is your base timing at? Make sure your vac advance is not stuck in the advanced position.

 

[Danger]

Broken oil pickup tube rattle

Just throwing this one out there for any future rattle seekers - I had a bad metallic rattle at 1300rpm that I just couldn't figure out. I had suspected it was coming from the inspection cover. I Dropped the oil pan and noticed that the oil pickup tube weld had broken off and it was slapping around in there. Easy fix!

 

[DirtDonk]

Wow, obscure issue there Danger! Glad you found that. Especially before something more dire happened.
Easy fix yes, but I wonder how many people would have thought to look there before more bad things happened?
Good find!

Paul