Need Help:Rattle/Buzz @ 2800 to 3000 rpm

[Timo04]

I have a rattle in my car that I have traced to the pictured bracket/heat-shield/baffle whatever it is called. Please click on the thumb nail below. What's not shown in the pic is the the small U channel rubber that I have fitted to the the bottom edge of this sheet metal bracket. I did this so that when the right and left side "belly pans" are installed they won't come into to direct metal on metal contact with this bracket and thereby resonate me out of the car! ;) Now the bottom of bracket is wedged with the rubber against the inside of the belly pans and seems to "flap" around less.

This U channel insulation did help somewhat and was a step in the right direction because the rattle used to be at 2000 rpm and was much more pronounced. Now the rattle is somewhat muffled and it seems to take more energy (higher engine rpm) to excite it. Also the pictured bracket used to be much looser fitting before the U channel rubber was installed. I did check the three screws on the mount near the in-let/out let coolant pipes and they are tight. Since I was not working from a lift this afternoon I feel that I could not get a clear shot and gain full access to inspect the entire bracket.

Lastly the reason why I suspect this bracket is the rattler is because when I tap on the bottom of the right side belly pan I can hear the vibration/rattle ever so slightly.

Does anyone have any tips on how to eliminate this annoying rattle?

Thanks in advance!

[John Allen]

do you have a header? The heat shield around it (that protecs the CV joint) is the one that I have always had trouble with. You usually have to put a slight bend in it along the longest edge to keep it from resonating.

[Will]

It seems like any time you have a flat metal plate with two or more mounting points, you get this. I would wrap the AC lines in insulation and then drill the plate and strap the AC lines to it, or strap it the other direction to the coolant pipes. First, check to make sure it's not vibrating against the coolant pipes, but fdon't be surprised if it's a "free air" vibration. I put a plate behind my aftermarket fuel pump with two mounting points and you could hear it 50 feet away.

[Timo04]

Thank you John & Will for the helpful replies! I will post a solution for this rattle if I can find one before the car is put away for the "off season".

[Frezer]

If we are collecting rattles, I can add two more of them:

When driving around 3000rpm, and throttle is released my spider top/cover (where you fold the top under) starts to resonate.

Another one, at idle, the shifter rods assembly is resonating. It can be improved by adding weight to the long rod going through the centre tunnel, but that's not nice for the bushes.

Cheers,
Merijn