HELP! Engine rattle on acceleration

[aveoryan]

Hello,

Newbie to the forum, and I have a 2006 aveo 1.6L 5dr manual with 93,xxx miles on it. I've been trying to track down this rattle and it's driving me nuts. No matter if im sitting still at idle or driving at any speed, when I hit the gas pedal I get a rattling sound coming from the front of the car that sounds like a bolt in a coffee can, or a heat sheild rattling on the exaust (which there isn't by the way, that was my first stop). It only occurs upon giving it gas, not while cruising or sitting at idle with my foot off the pedal. I know what rod knock and lifter tick sounds like, and it doesn't sound like that.

At first I thought it was exaust like the flex-pipe under the engine, but then I disconnected it from the CAT up front and tapped it with my hand and got no rattle. Then I took the (hollow) CAT off of the exhaust manifold and there was nothing jumping around in there either. The only other thing I can think of is to pull the engine pan to see if (got forbid) anything is loose like the oil pickup tube... I dont know... it's killing me.

The car drives and shifts absolutely fine other than the noise which is very annoying, It's only when I give it gas upon acceleration. HELP! Anyone else with this issue???

[avguy]

The only things that comes to mind quickly are the Deco valve cover being loose or that stupid ring on the flex pipe floating around making noise. But you know your way around cars, and so it's probably not either one of those obvious ones. Motor mounts, especially passenger side front have been know to go - did you check those? Did it start suddenly, and maybe after some repair work was done?

[Daox]

Have someone tap the gas while you're looking/hearing around the engine bay.

[aveoryan]

Oh yea I'm sorry, I forgot to mention that ring. I cut that off a long time ago because I thought it was that. Sadly it wasnt. I had not checked the mounts; I'll have to check that later tonight. I bought the car from an auction in the current state so I'm not sure of it's history or when it started for the previous owner, got a great deal but now I'm trying to fix this noise. I had someone revv the car while I was under it, and It sounds the loudest under the engine. I'm going to pop the oil pan to see if there is anything out of order tonight or tomorrow. Thanks for the replies....anyone else that this might sound familiar with any help is greatly appreciated. Thanks!

[USAFzac]

the bolts on my cat were loose.and.rattled.when i bought it. sounds like you know your stuff, but try moving the radiator, exhaust,battery tie down,etc by hand, see if anything has a loose bolt. mine was at anything over 20, gas or not. went away when i tightened all my bolts

[petrified.rabbit]

my guess would be the throw out bearing, or the timing belt tensioner.

if it is in the engine it would rattle just under more throttle, without the need to be moving. Does it? you say under acceleration, is that with load like driving? or just revving the engine? if it is on the engine, pull off the oil cap and see if you hear it more distinctively.

[aveoryan]

It doesn't matter if its sitting still or driving, when I give it throttle it makes the sound.

[mralx152]

im not the only one. My engine mounts snaped and my whole transmission houseing cracked but lucky I had a warranty happened right at 105k miles.

[jonelledge]

Yeah check the timing idler. Mine broke keeping just enough tention to keep the belt on. It rattled only pressing the gas or accleration and not at a idle. It wont hurt to check. Ifbitvis bad andbyou check it itll save you a replacement motor. At the very end mine jumped time one tooth causing a cylindrr missfire code to come on and decreasing power majorly (from what power thats bearly there)

[BrassBallsInc]

Is your catalytic converter plugged? Do you get a trouble code? A clogged cat will cause unburned fuel to detonate in the cat and the exhaust manifold, mimicking a low octane ping.