So this morning on the way to work my heat wouldn't work in my 03 R50 Justa'. When I got a mile away from work I stopped at a stoplight and my temp gauge started climbing from its happy middle zone to the blinky red light danger zone...quick. As I accelerated away from the light it dropped back to the middle so I took the chance of another red light to make it to work. After doing some research here, mini2, and pelican parts, as well as a call to the ever helpful Way and Century MINI I figured out what happened. Apparently I have a coolant leak and didn't notice. The fluid in the overfill reservoir got to low and the coolant system sucked in air. Apparently this causes there to be a blockage and the coolant to boil. Still not sure why this cuts the heat out? So on my lunch break I managed to get the coolant system bled, filled, and back up and running again. For a beginning tinkerer I am proud of myself but couldn't have done it alone! Thanks to all who are willing to help newbies like me!

 

The air lock causes voids in the coolant, so at times none is flowing through the heater coils; thence, no heat.

I drove my old small-block Camaro quite a while, nursing a leaky water pump...I could tell when it was *really* getting low on coolant, when the heat started to go. :-)

 

Ahhh that makes sense! Thanks! I'm guessing that the leak is coming from the coolant overflow tank...