Two weeks ago my car overheated. My coolant level was low. I refilled the coolant but now it is again extremely low. I have put cardboard under my car and don't seem to see a leak. Has anyone else had this problem? I'm not sure if it is only leaking when I am driving, or if it is leaking somewhere into my engine. HELP!!!!!!!!!!!! Any experience or advice would be greatly appreciated!

turn on the car, and look at your waterpump, if theres a lil bit of water spraying around from it, you have a bad pump. Most pumps have a lil bearing which shoots out with too much pressure, indicating the turbine in it dosent work, and it would shoot the water out, and you would overheat, so check it and be carefull, you can kill your car fast if its without a functioning waterpump.

Also look for any white smoke coming from the exhaust or engine. That would mean that coolant is getting into the engine somehow.

maybe a bad head gasket