My Daughter reported to me that her Mini (a 2006 cooper convertible) started overheating. It was low on coolant, so I added some, but it didn't make a difference.
It's not behaving like a normal overheating problem though -

Once it starts, it slowly climbs to about halfway up the temperature gauge, and then it stops there. You can drive it around, or let it sit, but after about 10 minutes, the electric fan turns on, and it quickly heats up to max.

I've never seen a car overheat like this before. Any idea what might cause that?

Note: the internal blower fan quit working also, not sure if that's related, doesn't seem to be thoug?

 

Good day!

It sound like the water pump isn't turning... It is heating up the coolant in the motor like normal, but once the thermostat opens, there is no flow thru the radiator... I had my 540i do that on the way home from work... It is a manual trans, so I just coasted until the coolant temp dropped... Then sped up quickly and coasted again... I turned off the motor when coasting... Made it home without the temp getting into the red...

Once the motor heats up, see how hot the top radiator hose is... It'll be hot by the motor, but cold or cooler by the radiator if you don't have any real flow...

Good luck!!!

CHeers!!!

 

Sound like the thermostat housing gasket, it leaks under pressure and evaporates on the engine block before you have a chance to see it. I would start there. I'm assuming you have a Justa, Non-S?

 

I wouldn't trust dumby electronic gauges.

I would flush the coolant, check the health of your components including water pump, check thermostat function, and make sure the low speed function on your radiator fan is working.

I'd imagine you'd be able to smell it pretty good if it was burning off a bunch of coolant.

 

He said he was losing coolant and that his fan would come on. On the R50's the recovery tank is not pressurized. I had an R50 that exhibited the same problem and when I checked the thermostat the housing gasket crumbled as I was taking it off. The R50 cooling system is slightly different than the R53. The slow pressurized leak coming from the, "Known for Failure" thermostat housing is almost undetectable, the coolant burns off on the hot engine block before is has a chance to reach the ground. When the car overheats, you will smell coolant all over the place, mostly from the gurgling recovery tank. I think his problem is under the battery box and the air intake... If I were him, I'd take those 2 items off and see if you see any moister or smell any coolant in that area. This is of course if he's talking about a Justa..

 

Good info! Thanks.

 

Ok, two things come to mind, but is it a Justa, or an S model?
If it is an S model (R53) with supercharger, the pump may have stopped turning, the tabs may have broken off the pump, the gears in the supercharger may have stripped off, or the coolant tank may be split, or possibly the crank pulley failed.
If it is a Justa, belt slipping, bad thermostat, water pump, etc can be an issue

 

Thanks for the replies everyone - I did some more checking and ended up replacing the Thermostat, gasket and a small plastic elbow (replaced with an aluminum part at the recommendation of a mechanic). No longer overheats, and drive fine. Didn't behave like the last Thermostat I had problems with (but then that was a 65 Impala! haha)

 

So glad to hear you got it back to good! Congrats!