Hello,I had a breakdown in my r50 03 cooper last weekend, and the new mechanic I had it towed to tried to tell me that i am checking my coolant level wrong. I use the coolant overflow tank markers to check it. He said that is wrong,and he said to take the thermastat cap off?? And I believe that is incorrect. I took the car home yesterday and the coolant level was registered in between min and max marks. This morning it is empty, I did not attempt to start it until I get more antifreeze. Also would a bad crankshaft sensor be the reason for the loss of coolant? Hopefully someone will see this and help clear my head.

 

Find a new guy. 1) you guys can’t communicate or 2) he is not familiar with cars 3) he’s lying. Your way is the way to do it. It will also be in the owners manual in the glovebox.

 

There is no such thing as a thermostat cap. He may have meant your coolant tank cap. Your method of reading coolant level is correct in that the level should be between min and max. Your problem is you apparently have a leak. A crankshaft sensor would not be the problem. You must identify and repair the coolant leak before doing anything else. A pressure test is the best method to identify the leak. Good luck.

 

On the R50 there is a cap on the thermostat housing.

Did you recently change/refresh the coolant? The R50 is notoriously hard to bleed. You don't fill em up using the expansion tank but by taking the thermostat housing cap off, get the engine up to temp and wait for the thermostat to open, while pouring coolant.

 

Thank you both for verification!! I am a woman and have been dealit with 4 mechanics since Oct 23! This new guy,who actually owns 4 Mini coopers is my newest issue of none of men don't believe that a woman can know what and how to make repairs and diagnosis problems for so many detailed issues. If I didn't have a medical condition that effects my fingers having no sensation, I could have done all of the repairs myself. It's exhausting!! Merry Christmas!!🙏✌️❤️🎄🇺🇸

 

+1 on the R50 design. Its got that one cap. Near the side of the engine. Filler cap.
Then the one near the back in the clear container. That's the reservoir and non pressured, has a NO windshield washer fluid sticker on it".
Then a small bleeder on the embow up by the front of the engine on the driver side.

https://www.mini2.com/threads/help-m...ew-plz.190132/

 

To add to that, there is also a small bleeder left of the battery box, on one of the two lines that go into the cabin.

 

The crank position sensor shouldn’t cause a coolant leak since it doesn’t contact the water jacket.

Did you notice any coolant underneath the car? As a wild guess, the thermostat housing on the R50 is plastic and somewhat prone to cracking.

 

Thank you for the info! Because I'm having that same issue again. This will be the 5th time in 3 years? I am praying that my latest mechanic is all he is told to be. They are mennonights, so I definitely trust them. Im also dealing with my brake lights not working at all to staying on all the time. Replaced the brake switch 3 times, got an OEM part the last time, and still had no brake lights. I lost my cruise control, and the ABS light on my dash went off.The OEM part restored my cruise control, but the ABS light is still off. So now I'm going to check the diode in the passenger footwell. If that's not it, then on to replacing or repairing the BCM. Let me know if you have any suggestions on repairing vs. replacing. Thank you!

 

+1 lights staying on means water got into the bcm

put a fan on it. or even better if you can, pull the panel and put a fan on it

*also check for corrosion / water damage on the bcm board