intermittent coolant leak

[PWJK12]

My gf has an 03 with an intermittent coolant leak. She has had it pressure tested three times now and they cant seem to find the leak. I personally have never seen the leak either. The coolant level seems to drop about once a week and we see coolant spray around the radiator...cant tell if its the neck or hose or something total different. I have read a little bit about it and think it might be the thermostat and gasket. I have been about to get my eyes on it as she is out of town this week. Do you guys have any suggestions or thoughts? Can anyone tell me where to tell her to look for the thermostat and its gasket? Thanks in advance!

[TheBMWPartStore]

Do you have a Cooper or Cooper S?

This is diagram of the Cooper S.

http://realoem.com/bmw/diagrams/h/n/153.png

This is a diagram of the Cooper.

http://realoem.com/bmw/diagrams/w/i/249.png

As far as getting the parts I have them in stock, and I recommend replacing both the thermostat (it comes with the gasket, and it's the only way to get the gasket) and the housing.

Cost for Cooper- $69.20
Cost for Cooper S-$63.98

Good luck and let me know if I can help!

[ScottinBend]

The thermostat housing on the S is notorious for leaking as the gasket can get brittle.

[ScottinBend]

The thermostat housing on the S is notorious for leaking as the gasket can get brittle.

[ScottinBend]

The thermostat housing on the S is notorious for leaking as the gasket can get brittle.

[ScottinBend]

The thermostat housing on the S is notorious for leaking as the gasket can get brittle.

[GreenBMW325is]

how many miles on the car, also check for proper cooling fan operation( with the a/c on you should hear the fan at a slow speed which mean stage 1 is working if not and you hear a load fan and it cycles on a off stage 2 is working), that can lead to coolant comsumption. also depending on miles the waterpump could be leaking. the thermostats are known for leaking(mini has revised the thermostat gasket).