My mini has been making a strange rattle when it is cold right around 1500rpm. When you start it everything is fine but when you start driving right as it hits 1500rpm it starts to make a rattle and when you get past 1800 rpm it goes away. The rattle goes away completely after about a minute of driving the car. I'm not sure if this is a characteristic of these motors or if this is timing chain related, any input would be greatly appreciated.

 

Quickest thing to check is your engine oil level. I keep mine above above 3/4 on the dipstick.

 

Mine is right around the 3/4 mark on the dipstick, I just checked it a couple nights ago.

 

Yea this is your timing chain. Mine did the same thing, same rpms and everything. My intake cam was off timing and guide rails broken.

 

My car sounds exactly like the sound that is heard in this video:
If it's the chain why does the sound go away after a minute or so of driving...

 

Because things warm up, are lubricated properly, etc.

This is the timing chain tensioner. I know it sucks, because I'm having this resolved for the 2nd time on a car with 95k miles.

Take your car to the dealership, have them measure the tensioner, and see if your car is covered by the extended warranty that MINI issued. Do this before your guides break and throw themselves all through your motor. That's how the motor eats itself, which is what happened to mine the first time.

Get your car to the dealership ASAP before it become a catastrophic failure.

 

Ok, I see that the tensioner online is roughly 20 bucks, so I'll just buy that and replace it. I see that there are two part numbers, 11-31-7-607-551-BOE and 11-31-4-609-482-BOE. Which is the one I need for a 2008 Cooper S?

 

This is not the solution, unfortunately. The only real fix is to replace the entire cassette with new guides, chain, and tensioner. Your chain may be stretched beyond working condition, and a new tensioner will do nothing good for this.

You really do not want to save this for later. It will destroy your motor. If you can get MINI to pay for repairs, it'll cost you nothing. If you pay for it now it'll cost like $2k at most. If you wait and it destroys your motor, it'll cost $4-5k.

 

Update, I added half a quart of oil today and the rattling has quieted down a lot, i don't even hear it anymore. I have a feeling that I'm just being stupid and can't read the dipstick the proper way.... I want to add more oil but at the same time I don't want to overfill it. I think I will order the updated tensioner regardless just to be on the safe side and replace it as preventative maintenance.