Rushing Sound on De-acceleration

[George Des]

I've got a 230sl with the 5 speed ZF box. I did a complete rebuild a few years back and have not driven it much due to some other more pressing projects. I took it on a long drive yesterday and noticed that as long as it is held at a constant speed or at acceleration everything is fine. However, when I let up on the accelerator there is a loud rushing sound that appears to be coming either from the right side of the transmission tunnel or from under the front passenger floor. I had the box rebuilt years ago and do not think this is anything internal to the box since everything else with it appears fine. I also replaced the flex disc after the first became damged after misalignment problems. Perhaps the flex disc is still not correct?  I have the Timevalve SS exhaust system installed and am wondering if this could be contacting the frame when it heats up and the sound is from the de-accelerting exhaust gases. Has anyone else experienced this problem and figured it out?

George

[ja17]

Hello George,

Make sure your exhaust heat shield is not coming loose.

[George Des]

Joe,

Thanks. I'm hoping that is all it is. I know the clearance next to the downpipes is pretty close. So close, I brought it to the attention of Timevalve when I spoke to them last time. For some reason or other I've had problems in that area before with other exhausu systems jts not as tight a clearance. the motor mounts and the trans mount are new. Could it possibly be the postioning of the front sub frame that is causeing the clearance issue? The subframe mounts are not brand new but they had been replaced about 15,000 miles ago at the max.

George

[ja17]

Hello George,

The heat  shield may just be loose.