Good morning,
When my engine is idling, I can hear a rattling from the engine. When I gently rev it, it sounds like marbles bouncing up and down.
I don't hear it when I'm outside of the vehicle, only when I'm inside.

The oil is fresh, but I'm wondering if it's bearings making the noise.

Also, sometimes when I'm driving fast, I smell something burning through the vents in the car.

Any idea what are causing my issues?

Thanks in advance.

 

Probably the timing chain tensioner is failing and you need to replace it. Not that difficult to do. Check out youtube, there is an instructional video on it. You should pop the hood and listen to where it is exactly coming from though first. Hopefully it isn't a spun rod bearing.


The smell could be oil seeping on to your exhaust and burning up.

 

Have someone press the clutch in and listen to see if the sound goes away...
If it does, it is the throwout bearing...part of the clutch.

 

What does the burning smell like specifically. Oil? Coolant? Rubber?

 

I don't think it smells like any of those, actually. Having previously driven a 99 Miata for years, I'm veeeeery familiar with oil and coolant smells.

Any other ideas?

 

Okay. I'll have someone help me with this.

 

Thanks, but the tensioner was changed 2 weeks ago, but the sound is still there. Any other ideas?

 

idk sounds like the SC is going out to me...

 

Check your crank damper. Loosen the belt and wiggle it, it may be coming apart.

 

I had a rattle on idle which just ended up being a worn rubber bushing on the SC tensioner hydraulic arm. Easy fix that one.

What RPM are you hearing the bag of marbles sound? definitely sounds the timing chain tensioner to me... maybe the replaced tensioner is faulty or there's bits of the tensioner guides in there?

 

Get yourself a nAutomotive stethoscope, about $10 at AutoZone. By poking around with the probe you will be able to pin point the source of the noise.