when it's cold...
 

I've noticed the past couple of times that I've started up my X in the morning it takes on this chugging sound. It's this faint puffing, almost like a steam engine or something. It only happens when it's cold outside, and it goes away after the X warms up. When I look at the exhaust I can see this kind of puffing action happening, nothing to serious, really faint. I'm not worried (unless I should be), but I would be interested in an engine-minded person's explaination as to why this happens. :dunno:

Which engine do you have?

If it's a diesel they have a special Webasto diesel fuelled heater which only runs when it's cold. It warms up the air conditioning much quicker and then turns off. There will be a small exhaust unit under the body below one of the front seats. On mine its under the passenger seat as mine is RHD.

No, I don't have a diesel. I've got the 3.0i petrol. I wish I could have the diesel though. :(

Coolant Reservoir replacement
 

Has anyone attempted to replace the coolant reservoir/tank in a '01 X5 3.0i?

The question for you is why? It's should be easy to replace it if it crack or broken.