Rattle sound when accelerating from 0 mph to 30

JUNIEYANEZ

MEMBER
2005 SUBARU OUTBACK
3.0L
6 CYL
TURBO
4WD
AUTOMATIC
200,000 MILES

When I surpass about 30 mph, I can accelerate without hearing the rattle. It’s not super loud I can turn the radio on and I won’t hear it. There does not seem to be a loss of power when accelerating either. Recently, my car was leaking colorless fumes into my car when I drove it for longer than 10 minutes and there was a louder rattle and delay of power when accelerating. I never took it to a mechanic, my dad looked at it. Next day my car has no loss of power and no fumes, turns out he only replaced my thermostat and that was somehow the problem? Not sure if these could be related, rattle never went away only got quieter. Only when accelerating from 0 mph. Anyone know what this could be? (Could be lots of things, I know) sorry I could not add more detail!

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,645 POSTS

Hi,

It can be a lot, but lets try to narrow it down. Can you tell approximately where the sound is coming from? If the vehicle is in neutral and you rev it, does it make noise?

Do me a favor, take a rubber mallet and tap on the exhaust system to see if you hear anything rattling. When I read your post, my first thought was a catalytic converter issue. Sometimes they come loose internally. As a result, you can get a rattling sound, experience power loss if it moves to a position that blocks exhaust flow, and it can cause you to get fumes in the vehicle.

Let me know. We'll figure it out, don't worry.

Joe