Why does mine moan @....

[jasonvibe]

My Vibe since day one has had a moan or burr sound @1900rpm no matter what gear I am in. It's really something noisey to me when starting out up hills or cruising on the flats at 45mph or so in OD. Especially in noticable in cooler weather(below 50 deg.). Is it the silly plastic cover on the engine or just a poorly fastened or designed heat shield on the exhaust vibrating? Could this be a low engine speed resonance point? But something should work to reduce this. I would remove the engine cover to do a test but I am not sure on how the plastic dodads on the back of the plastic engine cover release? Any one know for sure where/what the noise would be from? Dealers by me won't fix anything unless it's a leak or life and death danger to me or my family.

[stoutvibe]

I'm not sure if I had the same problem as you, but my vibe had that same noise right around 1800-1900 rpm, except I would have described it as more of a metalic vibration. As it turns out, one of the bolts attaching a heat shield between the engine and firewall was missing and causing the vibration. If you are laying under the car, look up directly behind the engine and you will see a curved heatshield. Just feel around, or look and there should be a total of 4 bolts holding it on. Good luck!

[jasonvibe]

I took a quick look from above(it was dark) and I see the heatshield covering the header pipes. Is that the heat shield you mean or is it further down on the collector pipe?

[stoutvibe]

The one you are refering to is not the correct one and that is probably my bad for not describing it well enough. There is one heat shield on the top that you are seeing which covers the top of the manifold. The shield is basically in two halves around the manifold assembly. There is a similar shield underneath the manifold. This is the one which I had the bolt missing from. You really can't see the bolts on this one from the top, but can see them pretty easily with a light from underneath.How I actually found the problem was to have my fiance in the car giving it some gas in neutral and getting it to make that noise. I just pushed around on the different heatshields until when I pushed on the one it the noise stopped an I knew. So, if you do check the bolts on the bottom manifold shield and they are all there, then have someone imitate the problem in the car while you try to locate the noise from underneath. Hope that helps

[jasonvibe]

do you have an AWD? I got under mine w/ramps. Not much of a view under an AWD. I did look again from the top and could feel 3 bolts on the "under shield". If there's a 4th...I can't see it or a hole where one should be even with a mirror. Could not find a picture in the manual on CD. Wish the manual had break down of components with the manifold for AWD's.

[stoutvibe]

Mine is just a base manual. I will see if I can take a decent picture of the underside of mine just for reference. Even on my base vibe it is somewhat difficult to access the bolts, but I am thinking probably much easier than on an AWD.

[jasonvibe]

a picture would be great. I am sure with the FWD it's easier to see. And with the AWD the extra drive hardware etc. makes it next to impossible to see much from under the car. It's actually easier to use a mirror and feel around from the top. On the under shield I found 2 driver's side, only 1 on the pass side. These are ones that hold the under shield directly to the header. Not the ones I see from the top. A pic may point me where to look for the 4th bolt. This is assuming the headers are similar. Someone I think said they were different...but my memory is not great on this.