Anyone know what might cause coolant to leak from the radiator cap, it will slowly seep out while the car is running. Basically my bro has been driving my car these last couple of weeks, he popped the hood and saw the coolant reservoir tank was almost empty (said he didn't notice any visible leaks then), he topped it off but filled it past he maximum line. Could this cause a leak? but now the coolant is between the min and max line and its still leaking? or could it just be a bad radiator cap or something else maybe?

 

The cap is probably worn; try a new OEM radiator cap they are cheap!

 

Overfilling the reservoir above the MAX line can cause it to overflow. During the normal operation of the engine heating up and cooling down, the engine needs the extra space above the MAX line to expand hot coolant into, which it then sucks back into the system once the engine cools down.

It could also be a bad cap. As stated, they are cheap - I would go ahead and replace it unless you know it's new already.

 

Replace the cap. They are cheap from the dealership or HondaPartsNow.