GenVibe - Community for Pontiac Vibe Enthusiasts

Hi all! I am new here, just bought a well-worn 2007 1.8L Vibe, and for the most part it seems to be working well. The main issue I am facing right now is that there is a annoying noise coming from the front when I accelerate. It seems most prevalent in 1st gear, but it does seem to be audible in 2nd and above albeit much quieter. Generally around the 2500rpm.

I ran the car without the serpentine belt and I was still able to hear the noise, so I don't think its related to that.

Thanks for any help

Here is a video with the sound (you can hear it most clearly at around 19 seconds): https://www.youtube.com/watch?v=gYcPPe8EBhE

Welcome to genvibe

Hard to say without hearing it, and hard to isolate when it only happens when the car is moving (accelerating in gear). Nice job trying it without the serpentine belt, that eliminates most of the usual suspects, and having it relate to engine speed and not vehicle speed eliminates a lot of others.

Maybe its something like an exhaust leak, or a loose heat shield.

If you can recreate the noise with the car in gear, one foot hard on the brake so the car doesn't move, and then rev the engine, maybe you can have someone you trust do that while you look in the open hood (from the side of the vehicle ) to try to source the noise

joatmon wrote: ↑Thu Jun 08, 2023 6:20 am Hard to say without hearing it

Sorry for such a late response, but I finally recorded a short video: https://www.youtube.com/watch?v=gYcPPe8EBhE

Its pretty difficult to hear in the video, I think its most prevalent around the 19 second mark.

I also had someone from a shop take a quick look at it and they thought it might be the timing chain, but they couldn't diagnose it unless they took the engine apart. I was hoping it was just a loose heat shield, but I've been poking around for a couple of days and haven't been able to find any candidates. Darn.

Oh also another thing: It seems to disappear immediately as soon as I let off the gas

Another long shot, but I had a relative's matrix suffer a failed upper motor mount, so bad that when the engine was under enough torque (accelerating), it would shift and open an exhaust joint. Found it by gunning the engine in gear with the brake pressed hard (not moving) and hood open, kinda scary to see how much the engine flopped around

joatmon wrote: ↑Thu Jun 15, 2023 2:36 pm Another long shot, but I had a relative's matrix suffer a failed upper motor mount, so bad that when the engine was under enough torque (accelerating), it would shift and open an exhaust joint. Found it by gunning the engine in gear with the brake pressed hard (not moving) and hood open, kinda scary to see how much the engine flopped around

This might be a very stupid question, but how can I put it in gear while braking without stalling it?

Another bizarre discovery I just made is that is does not rattle when in neutral and NOT moving (~2500rpm), but it will rattle when in neutral and the car IS moving (~2500rpm). No clue what this could mean though.

agd wrote: ↑Thu Jun 15, 2023 8:40 pm
This might be a very stupid question, but how can I put it in gear while braking without stalling it?

sorry about that, assumed it was an automatic transmission

I went to a different mechanic, and they don't think its a drive train issue. Instead, they think that there might be a carbon buildup which is causing detonation. I'm going to see if Seafoam helps

Any success diagnosing? My 07 makes similar noise around 3000 rpm.