My car has 183k and the radiator is leaking slowly - there is a small wet spot under the driver's side rear corner of the radiator every day. It is hard to tell if the leak is at the hose connection or at the joint between the aluminum and plastic; it is not leaking enough to see water spurting out and it seems to leak when cool as there are no drips when the car is running. I tightened the hose clamp but did no good.

I looked up the radiator and found there are more than one depending on whether the car has an oil cooler or not? I am not sure if I can trust the existing part number (if I could find it) because the current radiator was installed by the previous owner sometime before I got the car 2 years ago.

Is there a way to tell if the leak is the radiator tank or the hose?
How can I tell if my car has an oil cooler?
Does anyone know the correct radiator part number?
My VIN is WDBEA32E9RC148140

Thanks,
James