My wife says she saw some smoke from under the hood but determined it was the car's exhaust in front of her. Anyway.... I pop open the hood. I notice a little antifreeze under the expansion tank. Figure it may have been there from when I filled it not long ago. I run the car monitoring the water temperature. Car has no gauge so I use OBDLink on my phone. Temp goes up to 220. Thinking that's high I shut 'er down. T-stat is rated at 192F. Googling says 220 is normal. Well now it goes past 220 and I see water coming from the expansion tank seam. I hope that's all it it.
That wasn't so bad. The one thing on a first gen Mini that you can get to. Dealer had the expansion tank in stock. Just shows how often these things fail that they keep them around. At idle the water temperature got to 220 but it took a lot longer to get there than with the cracked tank. Then it creeped higher but no leak. At around 240 the electric fan kicked on and the temp dropped. Showing no signs of leaks. I took it out for a drive while monitoring the water temp. Varied from 194 to 215. Air temp is in the low 40s. I see why BMW got rid of real water gauges. I'm sure people panic when they see the needle move.
