I just did an oil change on my 07 MCS (Feb 07 build) and noticed that the coolant in the reservoir is green/brown color instead of the blue it should be. The oil was fine so I don't think is a blow head gasket (no chocolate milk). My SA is researching to see if there is TSB but I thought I would throw this out to the board also. Anybody have or heard of this issue? I did a thread search but no luck there.

 

Is it possible that you introduced an incompatable antifreeze with the OEM and you are getting a reaction. The only antifreeze that is recommended for the Mini in addition to the OEM stuff, is Zerex G05.

 

To my knowledge, no coolant has ever been added to my car. Not even at the first service interval according to the dealr SA. What is in there was put in at the factory. So unless Mini put in the wrong type.... Idonno

 

Then if you are satisfied that there is no leak, I would have them do a full fluid change and keep a good eye on it in the future.

 

I've seen this before on used MINIs. I think the stuff just turns brown after awhile.

 

How about in your car? Has the coolant color changed? I got my MCS 2 month after you according to your sig.

 

I haven't looked!
maybe later today after it gets daylight I'll check.

 

How many miles? I've a tick over 5000 and it is still Jolly Rancher Blue.

 

I first noticed it at 26K.

 

I just checked. My water is dirty gray looking. 29k miles.

 

Dirty gray or brown color coolant!!! . I think it is time to change it out, as it has picked up contaminents somewhere. These aluminium engines need the best of internal corrosion available for the longevity of the beast. I would not rely on Mini to fess up that their coolant sucks, because it is hard to prove and will be will be long out of warrenty.