My 2005 MCSC (34K miles.) has recently developed a very annoying exhaust rattle that is present only when the exhaust is cold. After running for several minutes the rattle goes away. If the car sits for 10 minutes then is restarted the rattle will come back but only for a very short time. It seems like it must be coming from an extremity of the exhaust which cools down and heats up quickly. The noise seems to come from somewhere in front of the mufflers. I've inspected all the heat shields and all the hangars and nothing appears loose. Plus the way it stops once the exhaust is warm makes me think it's not a heat shield. Anyone got a guess?

 

no guesses here. but my 02 MC has a similar exhaust rattle. but mine isn't particular as to when it is hot or cold. it does it pretty randomly. i put some downward pressure on the exhaust tip one of the few times that it was acting up while i wasn't driving and it stopped which led me to believe that it was a loose hangar. but i went through all the hangars and nothing was loose. so any help from anyone else would be much appreciated!! thanks in advance!

Jesse

 

check connections for tight and look for a cracked heat shield .

 

Today I got underneath and poked around some more while my daughter revved the engine lightly to cause the vibration. It seems that the noise is coming from the area of the square bracket that has the center exhaust hangar mounted on top. If I push up or pull down slightly on the exhaust pipe at that point the noise stops. So as a temporary fix I put a strap clamp around the pipe and bracket causing downward pressure. This eliminated the vibration as well as a start up clunk. Next I'll take the bracket off for a look.

 

The rubber mount that holds the hanger is probably torn causing the exhaust to vibrate. I had this problem with my '05. I replaced it for $60 and a month later it tore again. My exhaust shop came up with "a brilliant solution"..and weld new hangers and replacing the free swinging rubber mount with a solid rubber mount. If you don't like to feel your butt vibrating or your MINI turned into a kazoo at different speeds, I wouldn't recommend this solution at all.

 

I spoke too soon... A day after putting on the strap clamp the vibration was back and worse than ever. Strap clamp will be coming off along with the M7 USS piece that attaches to the square bracket.

Also, the center rubber hangars do not appear to be ripped.

 

This exhaust rattle continues to make me crazy! I've inspected everything - coupling between cat and rear is tight - and none of the hangars are loose or ripped.

The fact that it goes away once the car is fully warmed up makes me wonder if something is loose inside the exhaust. I've heard that internal baffles can go bad. Anyone had that happen? Is there a way to confirm that's the problem?

On the other hand putting pressure on exhaust tips or pressing up on either rear muffler stops the noise. This makes me think it's external.

All advice appreciated.

 

Took another look tonight. Put it up on stands and let it cool down. Then started up and looked for the rattle. Noticed water dripping from near the flange that connects the cat to the rear pipe. Closer inspection showed a hairline crack in the pipe about one inch back from the flange. The crack is on the edge of a weld bead. (I don't know if this weld is normal - it almost looks like a repair - but not one that I had done - I've owned since new) When the exhaust is cold, condensation and exhaust escape. Once hot, the exhaust expands and I can no longer feel any exhaust escaping. If I flex the exhaust I can easily widen the crack. Here's a picture:

http://s483.photobucket.com/albums/r...rent=Crack.jpg

Fix or replace? That is the question. I'm going to look into getting it welded. But am not optimistic.

Any exhaust recommendations from cabrio owners? (mine is a an '05 with M7 USS)