Having a problem that the dealership service center can't seem to replicate and was wondering if anyone else has had the same issue, and what it might be.

Here are the symptoms:

On cold starts, there's an audible rattle under the hood on the front passenger side. [Here's a video that may or may not be helpful: http://www.youtube.com/watch?v=oOjPk...feature=share]

During the first ten minutes of driving, the check engine light will come on for a few minutes, then turn back off. During this time there's also a rattle when the car shifts at around 2800 - 3200 rpms (automatic transmission).

This rattle during shifting seems to be in place of the usual "flutter" or "tweeting" noise I'd normally hear, but I can't tell for sure and I think that flutter is usually related to the turbo.

The dealership service guys tell me they let it sit overnight and started it up and could not hear anything - then of course the very next morning, I get the rattle at start up, rattle during shifting/acceleration, and check engine light. It's still under warranty so I'll need to take it back to them, but if I can go in with a little more information I think it may help. Any thoughts appreciated!

 

Update: The check engine light was possibly due to the knock sensor, which Mini says needs to be calibrated. (Wouldn't something cause this sensor to go off?)

No word yet on the rattle.

 

What year is your car and what kind of gas do you use? Rattle is probably the tensioner and/or chain, knock could be low octane or bad gas.

 

Thanks zrickety - it's a 2013 with about 18,500 miles. I use regular gas, so that could explain it. Would a dealer typically cite this as a problem/advise me to go with premium? They didn't really offer a reason as to what would trigger the sensor, just said it needed to be calibrated.

 

I've found in cold weather (15 deg F..) my 2013 makes all sorts of scary racket when cold.

Initially I thought timing chain issues (which on a low mile 2013 is not likely..), so I popped open the hood.. and started pressing around with a long screwdriver.. I found..

The top engine cover rattles.
The heat shield over the turbo rattles.

and..

The direct injection idle quality when cold is part of the issue.. it really sounds/shakes like a diesel..

Just something to keep in mind.

 

Thanks danjreed, that makes me feel better - I did pop the hood and noted that the engine cover does rattle. I was really scared about the tensioners and timing chain - this is my first new car and you always hear those horror stories about what happens when the warranty runs out.

My last car was an 02 Jetta TDI and you are right, the sound and shaking is kind of similar (though much louder on the older diesels of course).

A very knowledgeable automotive industry friend of mine did a little research and suggested it could be that a tensioner can't apply enough tension to the chain in very cold weather. I might have an independent mechanic take a look at that specifically just to be absolutely sure there is no timing chain issue.

 

The other thing to keep in mind.. is that its been a crazy cold winter here in NJ... (I'm sure you'll agree!)

ALL cars make strange noises in super cold weather. Mine is "new" too but I'm not worried.. I know they redesigned the tensioner (and a bunch of other things) in 2011.. and even then added small changes.. so 2013 should be a better/solid model year.

Just watched your video.. my Clubman makes the same sound when its super cold out.. until the engine warms up.. I'm pretty sure its just an exterior rattle from the covers/heat shields.. all the metal contracts and gives it a better chance to shake around.

BTW - Helix Motorsports - a Mini specialist is just outside of Philly. They will be my "go to" guys if I can't fix issues once the car is out of warranty.

 

Good to know - thanks for turning me on to Helix!

I'm glad I'm not the only one - thanks for the peace of mind.

My auto friend did mention that the timing chain problem was supposed to be addressed in the newer model too, so it sounds like everything should be just fine. *fingers crossed*