i noticed the car has been using coolant at a ridiculous rate.. i filled it to about the top the around 3 days ago, and today that damned light came back on.. i checked inside and the coolant bottle is filthy, looks like theres oil in there or something. i checked the TSRM and it doesn't say much on how to clean it except to flush it and re-fill it. but i'm pretty sure that won't do it, can i use water to clean it out? or would that be bad news.. any advice would be appreciated, thanks