I have a 2007 MCS with 54K miles. I've been hearing a strange sound starting last week that's gotten worse. When I start my car, and go to 2nd gear, as my RPMs go to around 2.5K I start hearing a strange sound from the front right of the car. I'm not sure how to describe the sound. It's a sound that I've never heard before in a car. It almost sounds like something like a compressor would sound like. If my RPMs are below 2K, no sound.

Usually by fourth gear the sound goes away. Or after a few minutes the sound goes away if I keep driving. But it's been getting worse as the week went on by. And now I get it even in first gear and it lasts longer.

It seems more noticeable when it's a cold day. It seems more noticeable when I'm making a turn.

Anyone have a clue on what this could be?

 

Could be you need the updated timing chain tensioner bolt ( 551) or entire swap out of the tensioner parts ( About 11 parts ) depending on measured deflection. More noticible when cold.

I have heard some R56 engines which sounded like diesels when this happens.

If you can take a look up under there today, make sure the tensioner bolt has not backed out causing oil loss and noise too.

 

Thanks for your help.

I tried recording the sound from my phone. Here are two clips.

http://dl.dropbox.com/u/280384/mini_sound1.mp3
http://dl.dropbox.com/u/280384/mini_sound2.mp3

In the first clip you can hear the sound at 4 seconds. The second clip is starting off from a stop and you can hear it whenever I accelerate.

Also, it seems to be horrible whenever I make a right turn. And it seems like temperature does not matter. It happened on a very hot day. And lastly, it takes about 2 hours or so after the engine is stopped before the sound comes back. So if I drive a hour after driving, the sound is not there. It's only when everything is cooled down.

Any other ideas? Or does this sound like the timing chain tensioner? I am not mechanically gifted so I wouldn't even know what to look for. I'll probably have to take it in. But is it dangerous to drive like this as this is my daily driver?

Thanks in advance.