Loud vibration sound

subaru
outback
vibration

#1

I have a 2004 outback with just over 100k miles on it. It has been making a loud vibrating sound lately. It makes the sound when idling and even louder when I step on the gas, but at highway speeds the sound disappears. I do not actually FEEL a vibration, it just sounds as though something is vibrating/rattling. We had a mechanic check it out and they thought it was an exhaust issue. Apparently not, because the sound is still there.


#2

You didn’t tell us where the sound is emanating from, but if it seems like it is coming from underneath the car, the most likely explanation is a loose or bent heat shield on the exhaust system.


#3

“We had a mechanic check it out and they thought it was an exhaust issue. Apparently not, because the sound is still there.”

Does this mean the mechanic changed something with the exhaust?


#4

Let’s start with locating it. Get about four feet of garden hose and use that as a stethoscope and locate the source of the noise.


#5

Sounds like the exhaust manifold heat shields have come loose. Happens frequently. First time I had them replaced at the dealer, very expensive. Second time I tied upper and lower shields together with a heavy gauge wire twist tie. Just drilled a hole in the standing seam of the lower shield and connected to an existing hole in the upper shield. No rattles since.