I've just discovered something a bit worrisome today. I have a nearly new (~2200 miles) 06 MCS and I decided to check the coolant in the reservoir (car was cool) & noticed a thin greasy film on top. It's not a whole lot, but you can see little tiny 'spheres' of the stuff floating on top. I stuck my finger in & it felt slippery with a consistency like thin vaseline or really thick vegetable oil almost. It didn't smell like motor oil at all & it was pretty much clear (other than the little bit of blue from the coolant). I looked at the oil cap & the dipstick & the oil is still pretty clear & shows no signs of coolant/water contamination. The car is running perfectly & shows no signs whatsoever of any problems. I did a search & didn't find anything really like this at all. Has anyone else seen or noticed anything like this before? I think I will call the dealer tomorrow as well & see what they say.

 

I wouldn't worry too much. Firstly, coolant feels a little oily to the touch anyway, and secondly, since oil is much lighter than water/coolant, all of it will eventually migrate to the surface of the coolant in the reservoir tank. It takes very little oil to cause an film to appear. In addition, despite parts cleaning, there is always residual cutting oil left over in water passages from the machining process. If it becomes more than a film (globs of oil) its time to worry.

 

Oil mixed with antifreeze has the look of a mud milkshake. Keep an eye on both the antifreeze & oil. If it gets worse get back to thee dealer asap. I'd guess it's OK though.

 

Thanks for the info. Yeah, maybe I'm being just a little paranoid. When I first saw it I immediately thought "blown head gasket?". But it really doesn't seem at all like motor oil & the car is running OK. I'll definitely keep an eye on it though. I guess it could very well be some left over cutting oil/grease because it did seem more like that.

 

Seems like most all new Minis have this problem. Not really sure it is a "problem" however, it is a known stiuation and your dealer will, if asked, flush your cooling systems and put in new antifreeze.