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Rattle with A/C on

1792 Views 13 Replies 9 Participants Last post by  407Driver
I have searched for this issue but can't find any other reports of it. When my A/C is turned on, and only when the A/C is on, I have a bad rattle noise that seems to come from the right side of the cabin. It is pretty loud and happens at roughly 2k-4k RPM of the engine. Has anyone run into this before? So far I have not been able to pinpoint where it is coming from, I can't even determine if it coming from the dash area or perhaps the engine.

Appreciate any help!
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Is the noise present only when the A/C is on, or with it off, and only the fan blower on.
Michael
I have a similar rattle. It didn't exist originally, but showed up after ~2 years. I figure something dropped into the nearly inaccessible area below the fuse box and rattles along the floor pan.
Is the noise present only when the A/C is on, or with it off, and only the fan blower on.
Michael
Only with the A/C on. If I turn the A/C (compressor) off and leave the fan on, the sound goes away. It tracks the A/C 100%.
You might want to check the compressor in the engine bay and the cooling fans up front.
Michael
I have a similar rattle. It didn't exist originally, but showed up after ~2 years. I figure something dropped into the nearly inaccessible area below the fuse box and rattles along the floor pan.
I have this too when I go around turns fast.

NOT air conditioner related though.
It is coming from the side of the car. There is a line that runs along the passenger side of the side sill that is now vibrating enough to hit the side sill. Take out your side scoop and put a piece of hose around the line and it should stop the noise.
It is coming from the side of the car. There is a line that runs along the passenger side of the side sill that is now vibrating enough to hit the side sill. Take out your side scoop and put a piece of hose around the line and it should stop the noise.
This sounds right. I was just working in the sill area and may have moved something around. Also, the sound is very uncentralized -- it could be emanating from the length of the sill.

I'll post again after I check it out. Thank you!
I've got the EXACT problem with my 06. I'll try the side vent inspection/modification as well.
Just got mine fixed. It turns out that there was a loose nut accessible from the passenger side front wheel well. With the nut night tightened down all the way the rattle has gone. I've also had the AC line that runs through the side sill rattle against the frame. Both issues are addressed now.
AC rattle result?

Hey guys I had posted the same exact noise on my O6 Elise recently. Its annoying as heck. I havent been able to check the AC line. Did this work for you and how easy or hard is it to remove the side scoop? Also will putting something on the line all the way near the scoop help the noise when it seems to come up from closer to the front?
I had this issue with my '06 Exige. It was corrected under warranty and was a relatively common problem. I recall that the a/c lines were zip tied into place to prevent them from vibrating (resulting in the rattle sound) under certain conditions.
Can anyone tell me how to remove the side scoop to access this? I dont want to accidentally break it by removing it incorrectly. Thanks.
Dont know about the side scoop? I fixed the rattle by removing the undertray, you can see the lines coming from the engine bay and enter the sill just in front of the rear wheel, a few tie wraps and some of that foam ac tube insulation stuffed into the sill cured it.
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